diff ref struct Rietveld refinement for the Mac · powder diffraction with X-rays, synchrotron and neutrons · started October 2026

Parameters: the theory

Parameters: the theory

The parameter dictionary (L044, L046): every parameter the core reads or will refine, under a readable name, with the equation it enters and where that equation comes from. The core's names, the app's help and this page are generated from the same file, so they cannot drift apart.

The papers' own equations have not yet been read against these: the session that wrote the dictionary could not reach the journals, so each equation is cited to the page where FullProf's manual or the microstructure paper prints it, and each paper's reference was checked against bibliographic records only. Where FullProf computes something other than its manual prints, the core's default follows the manual and the FullProf convention keeps FullProf's rule (L046).

102 entries, 90 refinable. Each gives the parameter's name in the core, its symbol, unit and meaning, the equation it enters with the paper behind it and the page where the equation is printed, its FullProf and GSAS-II equivalents, the range measured on the 240 .pcr files of the FullProf material that the core reads, the default, when to refine it (after FullProf's manual, p. 14) and the limits the engine holds it within. Generated from data/parameters.yml; do not edit by hand.

Radiation and instrument

Wavelength λ₁

wavelength_1 · \(\lambda_1\) · Å · refinable

The wavelength of the main line; with d it sets each Bragg angle.

\(\lambda_1 = 2 d_{hkl} \sin\theta_{hkl}\)

Equation as printed in: FullProf_Manual.pdf, p. 75. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Lambda1, line 8 (manual p. 75); also the WAVE line of a parametric resolution file, which replaces it (L042)
GSAS-II Lam1 (Lam for one line; GSASIIobj.py L666, defaultIparms.py L35)
Range X-rays 0.963–1.5406 (median 1.54056, Cu Kα1); neutrons 1.227–2.524 (median 1.87)
Default none: read from the .pcr
When to refine Not for laboratory data (known); for synchrotron and neutron data with a standard, together with the zero, the cell fixed (manual p. 83: "Cell parameters should be fixed if wavelength is to be refined").
Limits Above 0.001 Å. Refined for a pattern of one wavelength only, λ₂ moving with λ₁ as FullProf writes both (FP_tests/pb_ho.pcr and eight more patterns); a doublet's is refused (FullProf refines a single wavelength, p. 83; P18, L233).
Class global (FullProf's relaxation class; believed: the manual's LINE 9 names no class for the wavelength; it is coded on line 14 beside the zero)
Largest shift per cycle none
Correlated with cell_a, cell_b, cell_c: Bragg's law fixes λ/d, not λ and d apart: a wavelength k times larger with every cell edge k times longer gives the same peak positions (only the form factors and Debye–Waller terms at s = 1/2d tell them apart, weakly). Tip: Fix the cell at a standard's values when the wavelength is refined, as the manual says (p. 83). FullProf_Manual.pdf, p. 83
In the core Model.lambda

Wavelength λ₂

wavelength_2 · \(\lambda_2\) · Å · refinable

The wavelength of the second line of a doublet (Kα2); equal to λ1 for one line.

\(\lambda_2 = 2 d_{hkl} \sin\theta_{hkl,2}\)

Equation as printed in: FullProf_Manual.pdf, p. 75. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Lambda2, line 8 (p. 75)
GSAS-II Lam2 (defaultIparms.py L35)
Range 1.5443–1.5444 in the 29 files with a doublet
Default λ1 (no second line)
When to refine Never: fixed by the anode.
Limits Not refined by the engine (core 0.12.0): a .pcr that codes it is refused.
Class global (FullProf's relaxation class; believed: as wavelength_1)
Largest shift per cycle none
In the core Model.lambda

Intensity ratio λ₂/λ₁

wavelength_ratio · \(R_{21}\) · 1 · refinable

The intensity of the λ2 line relative to λ1; each reflection is added a second time at λ2 with this weight.

\(y_i \mathrel{+}= R_{21}\, I_h\, \Omega(2\theta_i - 2\theta_{h,2})\)

Equation as printed in: FullProf_Manual.pdf, p. 75. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Ratio, line 8 (p. 75)
GSAS-II I(L2)/I(L1) (GSASIIobj.py L667)
Range 0.43–0.50 (Cu Kα2/Kα1 about 0.5); negative values select separate widths for λ2
Default 0 (one line)
When to refine Rarely; fixed at the anode's value.
Limits \(\ge 0\).
Class global (FullProf's relaxation class; believed: the manual names no class for the ratio; a property of the pattern, as the global class's parameters)
Largest shift per cycle 0.05 1
In the core Model.ratio

Monochromator polarisation

monochromator_polarisation · \(C_{\mathrm{thm}} = \cos^2 2\theta_M\) · 1 · refinable

The polarisation by a monochromator at Bragg angle \(\theta\)_M, in the X-ray Lorentz–polarisation factor.

\(L_p = \frac{1 - K + K\, C_{\mathrm{thm}} \cos^2 2\theta}{2 \sin^2\theta \cos\theta}\)

Equation as printed in: FullProf_Manual.pdf, p. 53. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf computes twice eq. 3.26 for X-rays with K = ½ (L033); the default is eq. 3.26 (Convention::lorentz_polarisation), and the import doubles each structure phase's scale, exactly (L047, L050). The papers of manuals/papers/ do not set Lp.

FullProf Cthm, line 8 (p. 75); also the CTHM line of a parametric resolution file (L042)
GSAS-II Polariz. (GSASIIobj.py L668): a polarisation fraction in another formula (GSASIIpwd.py L224–241)
Range 0.79–0.98 in the X-ray files (median 0.80: graphite, Cu Kα); without a monochromator cos\(^{2}\) 0 = 1 (eq. 3.26), while 0 leaves out the angle dependence of the polarisation
Default 0 in a .pcr that does not give it; drs new takes 1 for X-rays without a monochromator (L155)
When to refine Never: fixed by the monochromator.
Limits Not refined by the engine (core 0.12.0).
Class global (FullProf's relaxation class; believed: not in the manual's list; a property of the pattern)
Largest shift per cycle none
In the core Model.cthm

Polarisation fraction

polarisation_fraction · \(K\) · 1 · refinable

The polarised fraction of a synchrotron beam (Ilo = 3), or the perfect-crystal fraction in flat-plate transmission (Ilo = 2).

\(L_p = \frac{1 - K + K\, C_{\mathrm{thm}} \cos^2 2\theta}{2 \sin^2\theta \cos\theta}\)

Equation as printed in: FullProf_Manual.pdf, p. 53. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

With Ilo = 3 and Cthm = 0 (no monochromator) FullProf takes C_thm as 1, cos\(^{2}\)2\(\theta\)_M of no deflection: FullProf's joint run prbaco (BM16, K = 0.1) is met so to rms 6·\(10^{-3}\), where 1 − K alone leaves every peak at 0.90 of FullProf's (runs/prbaco/prbaco_calc_1.prf, L322). Ilo = 3 with Cthm ≠ 0 is not checked.

FullProf Rpolarz, line 8 (p. 75)
GSAS-II Polariz. (GSASIIobj.py L668)
Range 0.03–0.5 in the 8 files that set it
Default 0; ½ is implied for characteristic X-rays
When to refine Rarely; synchrotron data with a known polarisation.
Limits Not refined by the engine (core 0.12.0).
Class global (FullProf's relaxation class; believed: not in the manual's list; a property of the pattern)
Largest shift per cycle none
In the core Model.rpolarz

Instrument resolution

instrument_resolution · \(U_i, V_i, W_i, X_i, Y_i, Z_i\) · deg\(^{2}\) (U, V, W), deg (X, Y, Z) · read, not refined

The instrument's Gaussian and Lorentzian widths, from a resolution file; added to the sample's.

\(H_{G,i}^2 = (U_i \tan\theta + V_i)\tan\theta + W_i,\quad H_{L,i} = X_i \tan\theta + \frac{Y_i}{\cos\theta} + Z_i\)

Equation as printed in: FullProf_Manual.pdf, p. 70. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

A TOF pattern's resolution file (Res = 5, 6; P05) gives instead Zero, Dtt1, Dtt2, Hodges' terms, \(\sigma\), \(\gamma\), α, β (ZD2TOF, ZD2TOT, SIGMA, GAMMA, ALFBE, ALFBT, TWOTH), added to the bank's and the phases' values (docs/TOF_FullProf.pdf): tof::Instrument.

FullProf Res and the file named on line 6 (p. 70); Res = 1–3 three functional forms, Res = 4 a table of 2\(\theta\), H_G, H_L
GSAS-II U, V, W, X, Y, Z of the instrument parameters (GSASIIobj.py L670–671)
Range the files of the runs: LaB6a.irf (Res = 1), Lab6_D500_Rennes.IRF (Res = 4)
Default none (no resolution file)
When to refine Never in the sample's refinement: measured on a standard.
In the core Model.instrumental, Model.tof

TOF bank angle 2θ

tof_bank_two_theta · \(2\theta_B\) · deg · read, not refined

The detector bank's scattering angle; it sets the Lorentz factor, the wavelength of each reflection and the absorption.

\(I_h \propto d_h^4 \sin\theta_B,\quad \lambda_h = 2 d_h \sin\theta_B\)

Equation as printed in: FullProf_Manual.pdf, p. 82. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

The d\(^{4}\) sin \(\theta\)_B Lorentz factor against FullProf's intensities: 0.9531/0.9533 (arg_si, 144.8°), 0.9997 (CeO2, 90°), 0.9943 (lamn_pol, 29.0°) (L341).

FullProf 2SinTh (2ThetaBank), line 14 (p. 82); TWOTH of a TOF resolution file replaces it
GSAS-II 2-theta (believed from GSAS-II's TOF instrument parameters, not checked line by line)
Range 28.955–174.02° on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default none: read
When to refine Never.
In the core Model.tof

Peak positions

Zero shift

zero_shift · \(2\theta_0\) · deg 2\(\theta\) · refinable

The offset of the detector's angle reading, added to every peak position.

\(2\theta_h = 2\arcsin\frac{\lambda}{2 d_h} + 2\theta_0 + S_c \cos\theta + S_s \sin 2\theta\)

Equation as printed in: FullProf_Manual.pdf, p. 56 · FullProf_Manual.pdf, p. 82. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

In a TOF pattern the zero is a time, T₀ in µs, on line 14 (p. 82): T_h = T₀ + Dtt1 d + Dtt2 d\(^{2}\) + Dtt_1overd/d (P05, tof_dtt1).

FullProf Zero, line 14 (p. 82)
GSAS-II Zero (GSASIIobj.py L672; position GSASIIstrMath.py L3561–3567)
Range −0.247 to 0.403 (median 0.047)
Default 0
When to refine Early, with the scale, the first background term and the cell (manual p. 14, step 2).
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 1 deg 2\(\theta\)
Correlated with sample_displacement, sample_transparency: All three move every peak: \(\Delta\)2\(\theta\) = 2\(\theta\)₀ + S_c cos \(\theta\) + S_s sin 2\(\theta\) (manual eqs. 3.37–3.39). Over the angles of one pattern cos \(\theta\) and sin 2\(\theta\) change slowly, so the three shifts are nearly proportional and the data hardly tell them apart. Tip: Refine the zero with the cell first; add S_c or S_s last and one at a time (manual p. 14, steps 2 and 9). FullProf_Manual.pdf, p. 56 · FullProf_Manual.pdf, p. 14
In the core Model.zero

Sample displacement

sample_displacement · \(S_c = -2s/R\) · deg 2\(\theta\) · refinable

The shift from a sample surface displaced by s from the goniometer axis (Bragg–Brentano), radius R.

\(\Delta 2\theta = -\frac{2s}{R}\cos\theta\)

Equation as printed in: FullProf_Manual.pdf, p. 56. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Sycos, line 14 (p. 82; meaning p. 56). FullProf 8.20 shifts by Sycos·cos 2\(\theta\), not by the manual's cos \(\theta\): its .prf ticks and .sub profiles (NdNi-HTO, cuf1k; L267), the compatibility rule Convention::displacement
GSAS-II Shift, in μm with the goniometer radius (GSASIIobj.py L673; GSASIIstrMath.py L3562–3564)
Range −0.079 to 0.145 in the 8 files that set it
Default 0
When to refine Late, with the transparency (p. 14, step 9); strongly correlated with the zero.
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 1 deg 2\(\theta\)
In the core Model.sycos

Sample transparency

sample_transparency · \(S_s = 1/(2\mu R)\) · deg 2\(\theta\) · refinable

The shift from the beam's penetration into a thick absorbing sample of linear absorption μ (Bragg–Brentano).

\(\Delta 2\theta = \frac{1}{2\mu R}\sin 2\theta\)

Equation as printed in: FullProf_Manual.pdf, p. 56. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Sysin, line 14 (p. 82; meaning p. 56)
GSAS-II Transparency, as 1/μ_eff in cm (GSASIIobj.py L676; GSASIIstrMath.py L3564)
Range −0.161 to 0.131 in the 5 files that set it
Default 0
When to refine Late (p. 14, step 9).
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 1 deg 2\(\theta\)
In the core Model.sysin

TOF Dtt1 (DIFC)

tof_dtt1 · \(D_1\) · µs/Å · refinable

The time of flight per Å of d-spacing: the bank's flight path and angle in one constant.

\(T_h = T_0 + D_1 d_h + D_2 d_h^2 + \frac{D_{-1}}{d_h}\)

Equation as printed in: FullProf_Manual.pdf, p. 82. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

The position's form: FullProf's .prf ticks follow it with Dtt_1overd; its .hkl and .out print Dtt1·d alone for Npr = 9 (L341).

FullProf Dtt1, line 14 of a TOF pattern (p. 82)
GSAS-II difC (believed from GSAS-II's TOF instrument parameters, not checked line by line)
Range 4570.6–49549.8 µs/Å on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern); 0 in lamn_pol_irf, whose resolution file gives it
Default none: read
When to refine Early, with the zero and the scale, on a standard; held for the sample.
Limits None.
Class global (FullProf's relaxation class; believed: the manual's LINE 9 names the zero's class (global, p. 77), and Dtt1 is on its line 14)
Largest shift per cycle none
In the core Model.tof

TOF Dtt2 (DIFA)

tof_dtt2 · \(D_2\) · µs/Ų · refinable

The quadratic term of the time of flight in d.

\(T_h = T_0 + D_1 d_h + D_2 d_h^2 + \frac{D_{-1}}{d_h}\)

Equation as printed in: FullProf_Manual.pdf, p. 82. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Dtt2, line 14 (p. 82); unused with Npr = 10
GSAS-II difA (believed from GSAS-II's TOF instrument parameters, not checked line by line)
Range −1.54–52.66 µs/Ų on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine After Dtt1, when the positions at long d need it.
Limits None.
Class global (FullProf's relaxation class; believed, as Dtt1)
Largest shift per cycle none
In the core Model.tof

TOF Dtt_1overd (DIFB)

tof_dtt_1overd · \(D_{-1}\) · µs·Å · refinable

The term of the time of flight in 1/d.

\(T_h = T_0 + D_1 d_h + D_2 d_h^2 + \frac{D_{-1}}{d_h}\)

Equation as printed in: FullProf_Manual.pdf, p. 82. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Dtt_1overd, line 14 of FullProf's newer files (its .out: "TOF=TOF+dtt_1overD/dsp"; the 2001 manual's line 14 has none)
GSAS-II difB (believed from GSAS-II's TOF instrument parameters, not checked line by line)
Range 0 on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine Rarely: short d-spacings with a strong absorption or a moderator term.
Limits None.
Class global (FullProf's relaxation class; believed, as Dtt1)
Largest shift per cycle none
In the core Model.tof

TOF thermal zero

tof_thermal_zero · \(T_{0t}\) · µs · refinable

The zero of the thermal neutrons' time of flight (Hodges).

\(T_h = n\,(T_0 + D_1 d_h) + (1 - n)\left(T_{0t} + D_{1t} d_h - \frac{D_{2t}}{d_h}\right),\quad n = \tfrac{1}{2}\operatorname{erfc}\!\left(w\,(x_c - d_h^{-1})\right)\)

Equation as printed in: FullProf_Manual.pdf, pp. 84–85. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

T to 0.003 µs against the .out of gabriela's 1288 reflections (L341).

FullProf Zerot, line 16 (Npr = 10, pp. 84–85)
GSAS-II none: GSAS-II has no epithermal–thermal crossover
Range gabriela's TOF pattern alone: 23.9607 µs (the one Npr = 10 run of L334)
Default none: read with Npr = 10
When to refine With a standard measured over the crossover; held for the sample.
Limits None.
Class global (FullProf's relaxation class; believed, as Dtt1)
Largest shift per cycle none
In the core Model.tof

TOF thermal Dtt1

tof_thermal_dtt1 · \(D_{1t}\) · µs/Å · refinable

The thermal neutrons' time of flight per Å.

\(T_h = n\,(T_0 + D_1 d_h) + (1 - n)\left(T_{0t} + D_{1t} d_h - \frac{D_{2t}}{d_h}\right),\quad n = \tfrac{1}{2}\operatorname{erfc}\!\left(w\,(x_c - d_h^{-1})\right)\)

Equation as printed in: FullProf_Manual.pdf, pp. 84–85. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

T to 0.003 µs against the .out of gabriela's 1288 reflections (L341).

FullProf Dtt1t, line 16 (pp. 84–85)
GSAS-II none: GSAS-II has no epithermal–thermal crossover
Range gabriela's TOF pattern alone: 7459.78 µs/Å (the one Npr = 10 run of L334)
Default none: read with Npr = 10
When to refine With a standard measured over the crossover; held for the sample.
Limits None.
Class global (FullProf's relaxation class; believed, as Dtt1)
Largest shift per cycle none
In the core Model.tof

TOF thermal Dtt2

tof_thermal_dtt2 · \(D_{2t}\) · µs·Å · refinable

The thermal neutrons' term in 1/d, subtracted.

\(T_h = n\,(T_0 + D_1 d_h) + (1 - n)\left(T_{0t} + D_{1t} d_h - \frac{D_{2t}}{d_h}\right),\quad n = \tfrac{1}{2}\operatorname{erfc}\!\left(w\,(x_c - d_h^{-1})\right)\)

Equation as printed in: FullProf_Manual.pdf, pp. 84–85. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

T to 0.003 µs against the .out of gabriela's 1288 reflections (L341).

FullProf Dtt2t, line 16 (pp. 84–85)
GSAS-II none: GSAS-II has no epithermal–thermal crossover
Range gabriela's TOF pattern alone: 19.952 µs·Å (the one Npr = 10 run of L334)
Default none: read with Npr = 10
When to refine With a standard measured over the crossover; held for the sample.
Limits None.
Class global (FullProf's relaxation class; believed, as Dtt1)
Largest shift per cycle none
In the core Model.tof

TOF crossover

tof_crossover · \(x_c\) · Å⁻¹ · refinable

The 1/d at which the epithermal and thermal times of flight cross.

\(T_h = n\,(T_0 + D_1 d_h) + (1 - n)\left(T_{0t} + D_{1t} d_h - \frac{D_{2t}}{d_h}\right),\quad n = \tfrac{1}{2}\operatorname{erfc}\!\left(w\,(x_c - d_h^{-1})\right)\)

Equation as printed in: FullProf_Manual.pdf, pp. 84–85. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

T to 0.003 µs against the .out of gabriela's 1288 reflections (L341).

FullProf x-cross, line 16 (pp. 84–85)
GSAS-II none: GSAS-II has no epithermal–thermal crossover
Range gabriela's TOF pattern alone: 1.264 Å⁻¹ (the one Npr = 10 run of L334)
Default none: read with Npr = 10
When to refine With a standard measured over the crossover; held for the sample.
Limits None.
Class global (FullProf's relaxation class; believed, as Dtt1)
Largest shift per cycle none
In the core Model.tof

TOF crossover width

tof_crossover_width · \(w\) · Å · refinable

How sharply the epithermal time of flight gives way to the thermal one.

\(T_h = n\,(T_0 + D_1 d_h) + (1 - n)\left(T_{0t} + D_{1t} d_h - \frac{D_{2t}}{d_h}\right),\quad n = \tfrac{1}{2}\operatorname{erfc}\!\left(w\,(x_c - d_h^{-1})\right)\)

Equation as printed in: FullProf_Manual.pdf, pp. 84–85. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

T to 0.003 µs against the .out of gabriela's 1288 reflections (L341).

FullProf Width, line 16 (pp. 84–85)
GSAS-II none: GSAS-II has no epithermal–thermal crossover
Range gabriela's TOF pattern alone: 2.363 Å (the one Npr = 10 run of L334)
Default none: read with Npr = 10
When to refine With a standard measured over the crossover; held for the sample.
Limits None.
Class global (FullProf's relaxation class; believed, as Dtt1)
Largest shift per cycle none
In the core Model.tof

Peak widths and shape

Caglioti U

caglioti_u · \(U\) · deg\(^{2}\) · refinable

The tan\(^{2}\)\(\theta\) term of the squared Gaussian width; with a resolution file, the sample's Gaussian strain.

\(H_G^2 = (U \tan\theta + V)\tan\theta + W + \frac{I_G}{\cos^2\theta}\)

Equation as printed in: Caglioti_Paoletti_Ricci_1958.pdf, pp. 224–225 · Thompson_Cox_Hastings_1987.pdf, p. 81 · FullProf_Manual.pdf, p. 45 · FullProf_Manual.pdf, p. 49 · Microstructural_effects.pdf, p. 4. Paper: G. Caglioti, A. Paoletti & F. P. Ricci (1958). Choice of collimators for a crystal spectrometer for neutron diffraction. Nucl. Instrum. 3, 223–228. doi:10.1016/0369-643X(58)90029-X

Caglioti's eq. 11 (p. 225) gives the squared Gaussian FWHM as a quadratic in a = tan \(\theta\) / tan \(\theta\)_M (eq. 5, p. 224); the names U, V, W are Rietveld's (1969), as Thompson, Cox & Hastings (eq. 4, p. 81) write it. No departure: the same in the default and in FullProf.

FullProf U, line 27 of the phase (p. 108)
GSAS-II U, a Gaussian variance \(\sigma\)² in centideg\(^{2}\), not H\(^{2}\) (GSASIIobj.py L670; GSASIIpwd.py L926)
Range −0.091 to 1.82 (median 0.163)
Default 0
When to refine With the peak shape (p. 14, step 4); with a resolution file, as the strain (step 10).
Limits \(\ge 0\) for a TCH phase over a resolution file, where U is the sample's strain alone; none otherwise, where U also carries the instrument's width and may be negative.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.5 deg\(^{2}\)
Correlated with caglioti_v, caglioti_w: H\(^{2}\) = U tan\(^{2}\)\(\theta\) + V tan \(\theta\) + W is a quadratic in tan \(\theta\) (Caglioti et al. 1958, eq. 11); over the range of tan \(\theta\) of one pattern its three coefficients compensate one another, V negative between U and W. Tip: Take U, V, W of the instrument from a standard (a resolution file) and refine only what the sample adds (manual p. 14). Caglioti_Paoletti_Ricci_1958.pdf, p. 225 · FullProf_Manual.pdf, p. 14
In the core Phase.u

Caglioti V

caglioti_v · \(V\) · deg\(^{2}\) · refinable

The tanθ term of the squared Gaussian width.

\(H_G^2 = (U \tan\theta + V)\tan\theta + W + \frac{I_G}{\cos^2\theta}\)

Equation as printed in: Caglioti_Paoletti_Ricci_1958.pdf, pp. 224–225 · Thompson_Cox_Hastings_1987.pdf, p. 81 · FullProf_Manual.pdf, p. 45 · FullProf_Manual.pdf, p. 49. Paper: G. Caglioti, A. Paoletti & F. P. Ricci (1958). Choice of collimators for a crystal spectrometer for neutron diffraction. Nucl. Instrum. 3, 223–228. doi:10.1016/0369-643X(58)90029-X

FullProf V, line 27 of the phase (p. 108)
GSAS-II V (GSASIIobj.py L670; GSASIIpwd.py L926)
Range −1.49 to 0.009 (median −0.354)
Default 0
When to refine With the peak shape (p. 14, step 4); fixed at 0 with a resolution file (manual p. 21).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.5 deg\(^{2}\)
In the core Phase.v

Caglioti W

caglioti_w · \(W\) · deg\(^{2}\) · refinable

The constant term of the squared Gaussian width.

\(H_G^2 = (U \tan\theta + V)\tan\theta + W + \frac{I_G}{\cos^2\theta}\)

Equation as printed in: Caglioti_Paoletti_Ricci_1958.pdf, pp. 224–225 · Thompson_Cox_Hastings_1987.pdf, p. 81 · FullProf_Manual.pdf, p. 45 · FullProf_Manual.pdf, p. 49. Paper: G. Caglioti, A. Paoletti & F. P. Ricci (1958). Choice of collimators for a crystal spectrometer for neutron diffraction. Nucl. Instrum. 3, 223–228. doi:10.1016/0369-643X(58)90029-X

FullProf W, line 27 of the phase (p. 108)
GSAS-II W (GSASIIobj.py L670; GSASIIpwd.py L926)
Range 0 to 0.494 (median 0.274)
Default 0
When to refine First of the widths (p. 14, step 4); fixed at 0 with a resolution file (p. 21).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.5 deg\(^{2}\)
In the core Phase.w

Gaussian size broadening

gaussian_size · \(I_G\) · deg\(^{2}\) · refinable

The Gaussian size broadening of the phase, the 1/cos\(^{2}\)\(\theta\) term of the squared Gaussian width.

\(H_{G,\mathrm{size}} = \frac{\sqrt{I_G}}{\cos\theta}\)

Equation as printed in: FullProf_Manual.pdf, p. 49 · Microstructural_effects.pdf, p. 4. Paper: J. Rodríguez-Carvajal. Study of micro-structural effects by powder diffraction using the program FullProf. Laboratoire Léon Brillouin (manuals/fullprof/docs/Microstructural_effects.pdf)

FullProf GausSiz (IG), line 27 of the phase (p. 108)
GSAS-II Size;mx (the Gauss–Lorentz mixing of the size term), the size itself in μm (GSASIIobj.py L651)
Range 0.018–0.172 in the 14 phases that set it
Default 0
When to refine With the microstructure (p. 14, step 10), over a resolution file.
Limits \(\ge 0\).
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.5 deg\(^{2}\)
Correlated with caglioti_u, caglioti_w: I_G enters H_G\(^{2}\) as I_G/cos\(^{2}\)\(\theta\) (manual p. 50–51), and 1/cos\(^{2}\)\(\theta\) = tan\(^{2}\)\(\theta\) + 1: a change of I_G is exactly a change of U and W by the same amount. Refined with U and W, I_G leaves a direction the data cannot fix, and the normal matrix is singular. Tip: Refine I_G only with the instrument's U and W fixed (from a resolution file). FullProf_Manual.pdf, p. 50 · FullProf_Manual.pdf, p. 51
In the core Phase.gauss_size

Lorentzian strain broadening

lorentzian_strain · \(X\) · deg · refinable

The tanθ term of the Lorentzian width of the TCH profile: the phase's Lorentzian strain.

\(H_L = X \tan\theta + \frac{Y}{\cos\theta}\)

Equation as printed in: Microstructural_effects.pdf, p. 4 · FullProf_Manual.pdf, p. 49 · Thompson_Cox_Hastings_1987.pdf, p. 80. Paper: J. Rodríguez-Carvajal. Study of micro-structural effects by powder diffraction using the program FullProf. Laboratoire Léon Brillouin (manuals/fullprof/docs/Microstructural_effects.pdf)

Thompson, Cox & Hastings have only the size term X/cos \(\theta\) (their X, eq. 8b, p. 82); FullProf's X tan \(\theta\) is the microstructure paper's Lorentzian strain (eq. 19, p. 4). The TCH (H, η) of eqs. 2–3 (p. 80) combine H_G and H_L. FullProf counts its peak window without X tan \(\theta\) (L035) and takes one more low point when X ≠ 0 (L042): Convention::peak_window, kept on import (no exact translation, L050).

FullProf X, line 27 of the phase (p. 108), Npr = 7
GSAS-II Y of the instrument (GSAS-II's tanθ term is Y, its 1/cosθ term X: GSASIIpwd.py L929); for the sample, Mustrain;i in units of \(10^{-6}\) (GSASIIobj.py L650)
Range −0.008 to 0.82 (median 0.119)
Default 0
When to refine With the peak shape (step 4), as strain over a resolution file (step 10).
Limits \(\ge 0\) for a TCH phase over a resolution file (the sample's strain alone); none otherwise.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.5 deg
In the core Phase.x

Lorentzian size broadening

lorentzian_size · \(Y\) · deg · refinable

The 1/cosθ term of the Lorentzian width of the TCH profile: the phase's Lorentzian (Scherrer) size.

\(H_L = X \tan\theta + \frac{Y}{\cos\theta},\qquad D = \frac{\lambda}{\beta^{*}\cos\theta}\)

Equation as printed in: Thompson_Cox_Hastings_1987.pdf, pp. 80–82 · FullProf_Manual.pdf, p. 49 · Microstructural_effects.pdf, p. 4. Paper: P. Thompson, D. E. Cox & J. B. Hastings (1987). Rietveld refinement of Debye–Scherrer synchrotron X-ray data from Al2O3. J. Appl. Cryst. 20, 79–83. doi:10.1107/S0021889887087090

Thompson, Cox & Hastings's X (F_L = X/cos \(\theta\), eq. 8b, p. 82) is FullProf's Y; GSAS-II also calls it X. No departure.

FullProf Y, line 27 of the phase (p. 108), Npr = 7
GSAS-II X of the instrument (its 1/cosθ term: GSASIIpwd.py L929); for the sample, Size;i in μm (GSASIIobj.py L651)
Range 0.005–0.348 (median 0.030)
Default 0
When to refine With the peak shape (step 4), as size over a resolution file (step 10).
Limits \(\ge 0\).
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.5 deg
Correlated with lorentzian_strain: H_L = X tan \(\theta\) + Y/cos \(\theta\) (manual p. 49; Thompson, Cox & Hastings 1987, pp. 80–82): both terms grow with \(\theta\), and over a short range of angles the two shapes are nearly proportional. Tip: Refine the size term Y first; the strain term X only with data over a wide range of angles. FullProf_Manual.pdf, p. 49 · Thompson_Cox_Hastings_1987.pdf, pp. 80–82
In the core Phase.y

Anisotropic strain, quartic form

quartic_strain · \(S_{HKL}\) · \(10^{-8}\) Å⁻⁴ · refinable

The coefficients of Stephens' quartic form in hkl, the variance of 1/d\(^{2}\) over the crystallites: a strain broadening that depends on the reflection.

\(\sigma^2(M_{hkl}) = 10^{-8}\sum_{H+K+L=4} S_{HKL}\,h^H k^K l^L,\quad D_{ST} = \sqrt{8\ln 2}\,\frac{180}{\pi}\,\frac{\sigma(M_{hkl})}{M_{hkl}},\quad H_G^2 \mathrel{+}= [(1-\xi)D_{ST}]^2\tan^2\theta,\quad H_L \mathrel{+}= \xi D_{ST}\tan\theta\)

Equation as printed in: FullProf_Manual.pdf, p. 22 · FullProf_Manual.pdf, p. 121 · NdNi_LTOa_calc1.mic. Paper: J. Rodríguez-Carvajal. Study of micro-structural effects by powder diffraction using the program FullProf. Laboratoire Léon Brillouin (manuals/fullprof/docs/Microstructural_effects.pdf)

Stephens' paper (J. Appl. Cryst. 32, 281, 1999) is not in the repository: the form, its factor \(10^{-8}\) and the split by ξ are as the manual (pp. 22, 121) and the .mic header state them, checked on FullProf's run of \(\mathrm{Nd_{2}NiO_{4}}\) (fullprof_anisotropic_strain, L211). FullProf's own forms of the trigonal, hexagonal and cubic classes and of −1 (the manual lists S_301 twice, p. 119) are not read yet; its strain model 8 (Str = 0, hexagonal, p. 29) is, as S_400 = Saa\(^{2}\), S_004 = Scc\(^{2}\), S_112 = 2 Saa Scc Cac, checked on its joint run scor_rxn (L322).

FullProf S_HKL, LINE 37 of the phase with |Str| = 1 and Strain-Model ≠ 0 (pp. 119–121); the terms of each Laue class in its order (Strain-Model 2, −2, 3 read: 1 2/m 1, 1 1 2/m, mmm)
GSAS-II Mustrain;i, generalized (the same quartic form, its coefficients scaled otherwise; GSASIIobj.py L650); not compared
Range −36.73 to 20.49 (NdNi_LTOa.pcr, the one file the core reads with them)
Default none (no anisotropic strain)
When to refine With the microstructure (p. 14, step 10), over a resolution file, once the isotropic U and X no longer account for the widths.
Limits None: an S_HKL may be negative (S_220 of \(\mathrm{Nd_{2}NiO_{4}}\) is −36.7); a negative sum gives no broadening.
Class profile (FullProf's relaxation class; Not named by the manual's LINE 9 (p. 77); believed profile, as LINES 26–38 are the phase's profile parameters (L211))
Largest shift per cycle none
Correlated with caglioti_u: S_HKL proportional to the square of the reciprocal metric (\(\sigma\)²(M) ∝ M\(^{2}\)) give a D_ST the same for every reflection, so a width (1 − ξ)²D_ST\(^{2}\) tan\(^{2}\)\(\theta\) that U tan\(^{2}\)\(\theta\) also gives (manual p. 22): refined together with U, that direction is not fixed by the data. Tip: Over a resolution file, refine U or the quartic form, not both, or hold U at zero. FullProf_Manual.pdf, p. 22
In the core Phase.quartic_strain

Anisotropic strain, Lorentzian share

quartic_strain_lorentzian · \(\xi\) · 1 · refinable

The share of the anisotropic strain's width taken by the Lorentzian part of the TCH profile; the rest is Gaussian.

\(H_G^2 \mathrel{+}= [(1-\xi)D_{ST}]^2\tan^2\theta,\quad H_L \mathrel{+}= \xi D_{ST}\tan\theta\)

Equation as printed in: FullProf_Manual.pdf, p. 22 · FullProf_Manual.pdf, p. 121 · NdNi_LTOa_calc1.mic. Paper: J. Rodríguez-Carvajal. Study of micro-structural effects by powder diffraction using the program FullProf. Laboratoire Léon Brillouin (manuals/fullprof/docs/Microstructural_effects.pdf)

As the .mic header writes it (lines 36–38): the Gaussian strain (U + [(1 − ξ)D_ST]²) tan\(^{2}\)\(\theta\), the Lorentzian (X + ξ D_ST) tan \(\theta\).

FullProf XI, LINE 38 of the phase ("Lorentzian strain coeff.", p. 121)
GSAS-II Mustrain;mx (the Gauss–Lorentz mixing of the strain, GSASIIobj.py L650); not compared
Range 0.136 (NdNi_LTOa.pcr)
Default 0
When to refine With the quartic form, once its S_HKL are found.
Limits 0 to 1.
Class profile (FullProf's relaxation class; Not named by the manual's LINE 9 (p. 77); believed profile, as the quartic form (L211))
Largest shift per cycle none
Correlated with lorentzian_strain: ξ D_ST tan \(\theta\) adds to X tan \(\theta\) in H_L: where D_ST hardly depends on hkl, ξ and X move the same width. Tip: Refine ξ with X fixed, or X with ξ fixed. NdNi_LTOa_calc1.mic
In the core Phase.quartic_strain

Anisotropic size by shape

shape_size · \(S_Z\) · 1 · refinable

The Lorentzian size broadening of crystallites of a shape: platelets (|cos φ|), needles (sin φ), φ the angle between the scattering vector and the platelets' normal or the needles' axis; or the antiphase domains of \(\mathrm{Cu_{3}Au}\), broadening the reflections whose h, k, l are not all of one parity.

\(H_L \mathrel{+}= \frac{360}{\pi^2}\,10^{-3}\,\lambda\, S_Z\, g(\mathbf{h})/\cos\theta,\quad g = |\cos\varphi|,\ \sin\varphi\ \text{or}\ 1\)

Equation as printed in: FullProf_Manual.pdf, p. 23 · FullProf_Manual.pdf, p. 24 · prba10k_calc.out · pdfinal_calc.out. Paper: J. Rodríguez-Carvajal. Study of micro-structural effects by powder diffraction using the program FullProf. Laboratoire Léon Brillouin (manuals/fullprof/docs/Microstructural_effects.pdf)

k_s = (360/π²) λ \(10^{-3}\) as the manual gives it for the quadratic form of size (p. 23); the needles' sin φ and the platelets' |cos φ| as on p. 24. FullProf's vector is taken as a direction [u v w] of the crystal; prba10k's [0 0 1] in a tetragonal cell cannot tell it from a reciprocal one (L267).

FullProf LorSiz with Size-Model 1, −1 (LINE 27, the vector on LINE 36) or −14 (pp. 108, 118)
GSAS-II Size;a, the uniaxial size along an axis (GSASIIobj.py L651); a different form, not compared
Range 0.058 (prba10k, needles), 9.99 (Pd3MnD, antiphase)
Default 0
When to refine After the isotropic size Y, when the widths depend on the direction of h.
Limits \(\ge 0\).
Class profile (FullProf's relaxation class; Not named by the manual's LINE 9 (p. 77); believed profile, as Y (L267))
Largest shift per cycle none
Correlated with lorentzian_size: Both add to H_L over cos \(\theta\): where g(h) varies little among the reflections, S_Z and Y move the same widths. Tip: Refine Y first, then S_Z with reflections of several directions in the range. prba10k_calc.out
In the core Phase.shape_size

Pseudo-Voigt η₀

pv_eta0 · \(\eta_0\) · 1 · refinable

The Lorentzian fraction of the pseudo-Voigt profile (Npr = 5) at 2\(\theta\) = 0.

\(\Omega = \eta L + (1-\eta) G,\quad \eta = \eta_0 + X\, 2\theta\)

Equation as printed in: FullProf_Manual.pdf, p. 44 · FullProf_Manual.pdf, p. 45. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Shape1, line 26 of the phase (p. 108), Npr = 5
GSAS-II none: GSAS-II mixes by the TCH widths (GSASIIpwd.py L967)
Range −0.014 to 0.78 (median 0.147) in 47 phases
Default 0
When to refine With the peak shape (step 4).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.2 1
In the core Phase.eta0

Pseudo-Voigt η slope

pv_eta_slope · \(X_\eta\) · 1/deg · refinable

The linear change of the pseudo-Voigt mixing η with 2\(\theta\) (Npr = 5); the same .pcr field as the TCH's X.

\(\eta = \eta_0 + X_\eta\, 2\theta\)

Equation as printed in: FullProf_Manual.pdf, p. 45. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf X, line 27 of the phase (p. 108), Npr = 5
GSAS-II none
Range as X above (the field is shared)
Default 0
When to refine With the peak shape (step 4), after η0.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.005 1/deg
In the core Phase.x

TOF σ₀

tof_sigma0 · \(\sigma_0\) · µs\(^{2}\) · refinable

A term of the variance of the Gaussian part of a TOF peak.

\(\sigma_h^2 = \sigma_0 + \sigma_1 d_h^2 + \sigma_2 d_h^4 + \sigma_Q d_h,\quad H_G = \sqrt{8 \ln 2\, \sigma_h^2}\)

Equation as printed in: FullProf_Manual.pdf, p. 111. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

HwG of FullProf's .out met (L341).

FullProf Sig-0, line 27 (p. 111)
GSAS-II sig-0
Range −0.750–3.015 µs\(^{2}\) on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine \(\sigma\)₁ first, then \(\sigma\)₂ and \(\sigma\)₀ (p. 111: \(\sigma\)₀ simultaneously with \(\sigma\)₂ only when needed).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF σ₁

tof_sigma1 · \(\sigma_1\) · µs\(^{2}\)/Ų · refinable

A term of the variance of the Gaussian part of a TOF peak.

\(\sigma_h^2 = \sigma_0 + \sigma_1 d_h^2 + \sigma_2 d_h^4 + \sigma_Q d_h,\quad H_G = \sqrt{8 \ln 2\, \sigma_h^2}\)

Equation as printed in: FullProf_Manual.pdf, p. 111. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

HwG of FullProf's .out met (L341).

FullProf Sig-1, line 27 (p. 111)
GSAS-II sig-1
Range 0.223–90.875 µs\(^{2}\)/Ų on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine \(\sigma\)₁ first, then \(\sigma\)₂ and \(\sigma\)₀ (p. 111: \(\sigma\)₀ simultaneously with \(\sigma\)₂ only when needed).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF σ₂

tof_sigma2 · \(\sigma_2\) · µs\(^{2}\)/Å⁴ · refinable

A term of the variance of the Gaussian part of a TOF peak.

\(\sigma_h^2 = \sigma_0 + \sigma_1 d_h^2 + \sigma_2 d_h^4 + \sigma_Q d_h,\quad H_G = \sqrt{8 \ln 2\, \sigma_h^2}\)

Equation as printed in: FullProf_Manual.pdf, p. 111. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

HwG of FullProf's .out met (L341).

FullProf Sig-2, line 27 (p. 111)
GSAS-II sig-2
Range −77.22–12.54 µs\(^{2}\)/Å⁴ on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine \(\sigma\)₁ first, then \(\sigma\)₂ and \(\sigma\)₀ (p. 111: \(\sigma\)₀ simultaneously with \(\sigma\)₂ only when needed).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF σ_Q

tof_sigma_q · \(\sigma_Q\) · µs\(^{2}\)/Å · refinable

A term of the variance of the Gaussian part of a TOF peak.

\(\sigma_h^2 = \sigma_0 + \sigma_1 d_h^2 + \sigma_2 d_h^4 + \sigma_Q d_h,\quad H_G = \sqrt{8 \ln 2\, \sigma_h^2}\)

Equation as printed in: FullProf_Manual.pdf, p. 111. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

\(\sigma\)_Q·d as GSAS-II's sig-q, believed: alum's 0.001 is below the print of FullProf's .out (L341).

FullProf Sigma-Q, line 27 of FullProf's newer files (the 2001 manual's Xt)
GSAS-II sig-q (GSASIIpwd.py L2510)
Range 0–0.001 µs\(^{2}\)/Å on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine \(\sigma\)₁ first, then \(\sigma\)₂ and \(\sigma\)₀ (p. 111: \(\sigma\)₀ simultaneously with \(\sigma\)₂ only when needed).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF γ₀

tof_gamma0 · \(\gamma_0\) · µs · refinable

A term of the FWHM of the Lorentzian part of a TOF peak.

\(H_{L,h} = \gamma_0 + \gamma_1 d_h + \gamma_2 d_h^2\)

Equation as printed in: FullProf_Manual.pdf, p. 111. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

H and η from H_G and H_L by the Thompson–Cox–Hastings relations: FullProf's Hw and ETA met (L341).

FullProf Gam-0, line 27-2 (p. 111)
GSAS-II Z (believed from GSAS-II's TOF instrument parameters, not checked line by line)
Range 0 µs on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine \(\gamma_1\) after the Gaussian terms, for a sample's size and strain.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF γ₁

tof_gamma1 · \(\gamma_1\) · µs/Å · refinable

A term of the FWHM of the Lorentzian part of a TOF peak.

\(H_{L,h} = \gamma_0 + \gamma_1 d_h + \gamma_2 d_h^2\)

Equation as printed in: FullProf_Manual.pdf, p. 111. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

H and η from H_G and H_L by the Thompson–Cox–Hastings relations: FullProf's Hw and ETA met (L341).

FullProf Gam-1, line 27-2 (p. 111)
GSAS-II X (believed from GSAS-II's TOF instrument parameters, not checked line by line)
Range 0–5.369 µs/Å on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine \(\gamma_1\) after the Gaussian terms, for a sample's size and strain.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF γ₂

tof_gamma2 · \(\gamma_2\) · µs/Ų · refinable

A term of the FWHM of the Lorentzian part of a TOF peak.

\(H_{L,h} = \gamma_0 + \gamma_1 d_h + \gamma_2 d_h^2\)

Equation as printed in: FullProf_Manual.pdf, p. 111. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

H and η from H_G and H_L by the Thompson–Cox–Hastings relations: FullProf's Hw and ETA met (L341).

FullProf Gam-2, line 27-2 (p. 111)
GSAS-II Y (believed from GSAS-II's TOF instrument parameters, not checked line by line)
Range 0 µs/Ų on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine \(\gamma_1\) after the Gaussian terms, for a sample's size and strain.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

Peak asymmetry

Bérar–Baldinozzi asymmetry

berar_baldinozzi · \(P_1, P_2, P_3, P_4\) · 1 · refinable

The four coefficients of the empirical asymmetry multiplier, below AsyLim.

\(A(u) = 1 + \frac{P_1 F_a(u) + P_2 F_b(u)}{\tan\theta_h} + \frac{P_3 F_a(u) + P_4 F_b(u)}{\tan 2\theta_h},\ u = \frac{2\theta_h - 2\theta}{H},\ F_a = 2u e^{-u^2},\ F_b = (8u^3 - 12u) e^{-u^2}\)

Equation as printed in: Berar_Baldinozzi_1993.pdf, pp. 128–129 · FullProf_Manual.pdf, p. 54. Paper: J.-F. Bérar & G. Baldinozzi (1993). Modeling of line-shape asymmetry in powder diffraction. J. Appl. Cryst. 26, 128–129. doi:10.1107/S0021889892009725

The paper's u is positive on the low-angle side (eqs. 1–3, p. 128), as FullProf computes it; the manual's eq. 3.29 prints the opposite sign. FullProf's F_b = (4u\(^{2}\) − 3)F_a is the paper's + 3F_a (L035): Convention::berar_baldinozzi; a .pcr's (P1, P2, P3, P4) are imported as (P1 + 3P2, P2, P3 + 3P4, P4), exactly (L050).

FullProf Asy1–Asy4 (PA1–PA4), line 30 of the phase (p. 109)
GSAS-II none: GSAS-II uses FCJ only
Range P1 −0.383 to 0.294 (63 phases), P2 0.015–0.104 (42), P3 −0.153 to 1.258 (4), P4 never set
Default 0
When to refine With the peak shape (p. 14, step 4), starting near 0.01 (p. 54).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.5 1
In the core Phase.asym

Axial divergence S/L

axial_divergence_s_l · \(S/L\) · 1 · refinable

The sample half-height S over the goniometer radius L, in the Finger–Cox–Jephcoat axial-divergence profile.

\(2\phi_{\min} = \arccos\left(\cos 2\theta \sqrt{\left(\tfrac{H+S}{L}\right)^2 + 1}\right),\quad 2\phi_{\mathrm{infl}} = \arccos\left(\cos 2\theta \sqrt{\left(\tfrac{H-S}{L}\right)^2 + 1}\right)\)

Equation as printed in: Finger_Cox_Jephcoat_1994.pdf, pp. 893–895 · FullProf_Manual.pdf, p. 69 · FullProf_Manual.pdf, p. 112. Paper: L. W. Finger, D. E. Cox & A. P. Jephcoat (1994). A correction for powder diffraction peak asymmetry due to axial divergence. J. Appl. Cryst. 27, 892–900. doi:10.1107/S0021889894004218

FullProf (CrysFML's Prof_Val, lines 1289–1294) reads a pair with D_L < 0.0002 as (H/L + S/L, H/L − S/L), so S_L alone means S/L = H/L = S_L/2; the default takes the paper's S/L and H/L as given (Convention::axial_divergence), and a .pcr's pair is imported through profile::fullprof_axial, exactly (L050).

FullProf S_L, line 30 of the phase (p. 109), Npr = 7; the ASYM line of a parametric resolution file adds to it (L042)
GSAS-II SH/L, S/L and H/L taken equal (GSASIIobj.py L669)
Range 0.030–0.140 (median 0.064) in 28 phases
Default 0
When to refine With the peak shape (step 4); often fixed from the instrument.
Limits \(\ge 0\).
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.02 1
In the core Phase.s_l

Axial divergence H/L

axial_divergence_d_l · \(D/L\) · 1 · refinable

The detector half-opening H over the goniometer radius L (FCJ's H/L), in the Finger–Cox–Jephcoat profile.

\(2\phi_{\min} = \arccos\left(\cos 2\theta \sqrt{\left(\tfrac{H+S}{L}\right)^2 + 1}\right),\quad 2\phi_{\mathrm{infl}} = \arccos\left(\cos 2\theta \sqrt{\left(\tfrac{H-S}{L}\right)^2 + 1}\right)\)

Equation as printed in: Finger_Cox_Jephcoat_1994.pdf, pp. 893–895 · FullProf_Manual.pdf, p. 69 · FullProf_Manual.pdf, p. 112. Paper: L. W. Finger, D. E. Cox & A. P. Jephcoat (1994). A correction for powder diffraction peak asymmetry due to axial divergence. J. Appl. Cryst. 27, 892–900. doi:10.1107/S0021889894004218

FullProf (CrysFML's Prof_Val, lines 1289–1294) reads a pair with D_L < 0.0002 as (H/L + S/L, H/L − S/L), so S_L alone means S/L = H/L = S_L/2; the default takes the paper's S/L and H/L as given (Convention::axial_divergence), and a .pcr's pair is imported through profile::fullprof_axial, exactly (L050).

FullProf D_L, line 30 of the phase (p. 109), Npr = 7
GSAS-II SH/L, taken equal to S/L (GSASIIobj.py L669)
Range 0.020–0.036 in 16 phases
Default 0
When to refine With S/L; the two are strongly correlated.
Limits \(\ge 0\).
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.02 1
In the core Phase.d_l

TOF α₀

tof_alpha0 · \(\alpha_0\) · µs\(^{-1}\) · refinable

The constant of the rise of a TOF peak (its leading exponential).

\(\alpha_h = \alpha_0 + \frac{\alpha_1}{d_h} + \frac{\alpha_Q}{\sqrt{d_h}},\quad \beta_h = \beta_0 + \frac{\beta_1}{d_h^4} + \frac{\beta_Q}{d_h^2}\)

Equation as printed in: FullProf_Manual.pdf, p. 112 · TOF_FullProf.pdf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

With Npr = 10 α₀ + α₁ d is a time (µs) mixed with the thermal one as 1/α (the 2003 document's Panel 10); α_Q, β_Q found from alum's .out to its six digits (L341).

FullProf alph0, line 30 (p. 112)
GSAS-II none (GSAS-II's alpha has the 1/d term alone)
Range 0 µs\(^{-1}\) on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine With a standard; α₁ and β₀, β₁ first (p. 112).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF α₁

tof_alpha1 · \(\alpha_1\) · µs\(^{-1}\)·Å · refinable

The 1/d term of the rise of a TOF peak.

\(\alpha_h = \alpha_0 + \frac{\alpha_1}{d_h} + \frac{\alpha_Q}{\sqrt{d_h}},\quad \beta_h = \beta_0 + \frac{\beta_1}{d_h^4} + \frac{\beta_Q}{d_h^2}\)

Equation as printed in: FullProf_Manual.pdf, p. 112 · TOF_FullProf.pdf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

With Npr = 10 α₀ + α₁ d is a time (µs) mixed with the thermal one as 1/α (the 2003 document's Panel 10); α_Q, β_Q found from alum's .out to its six digits (L341).

FullProf alph1, line 30 (p. 112)
GSAS-II alpha (believed from GSAS-II's TOF instrument parameters, not checked line by line)
Range 3·\(10^{-6}\)–0.717 µs\(^{-1}\)·Å on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine With a standard; α₁ and β₀, β₁ first (p. 112).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF α_Q

tof_alpha_q · \(\alpha_Q\) · µs\(^{-1}\)·Å^½ · refinable

The 1/√d term of the rise of a TOF peak.

\(\alpha_h = \alpha_0 + \frac{\alpha_1}{d_h} + \frac{\alpha_Q}{\sqrt{d_h}},\quad \beta_h = \beta_0 + \frac{\beta_1}{d_h^4} + \frac{\beta_Q}{d_h^2}\)

Equation as printed in: FullProf_Manual.pdf, p. 112 · TOF_FullProf.pdf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

With Npr = 10 α₀ + α₁ d is a time (µs) mixed with the thermal one as 1/α (the 2003 document's Panel 10); α_Q, β_Q found from alum's .out to its six digits (L341).

FullProf alphQ, line 30 of FullProf's newer files
GSAS-II none
Range −0.1046–0 µs\(^{-1}\)·Å^½ on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine With a standard; α₁ and β₀, β₁ first (p. 112).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF β₀

tof_beta0 · \(\beta_0\) · µs\(^{-1}\) · refinable

The constant of the decay of a TOF peak (its trailing exponential).

\(\alpha_h = \alpha_0 + \frac{\alpha_1}{d_h} + \frac{\alpha_Q}{\sqrt{d_h}},\quad \beta_h = \beta_0 + \frac{\beta_1}{d_h^4} + \frac{\beta_Q}{d_h^2}\)

Equation as printed in: FullProf_Manual.pdf, p. 112 · TOF_FullProf.pdf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

With Npr = 10 α₀ + α₁ d is a time (µs) mixed with the thermal one as 1/α (the 2003 document's Panel 10); α_Q, β_Q found from alum's .out to its six digits (L341).

FullProf beta0, line 30 (p. 112)
GSAS-II beta-0 (believed from GSAS-II's TOF instrument parameters, not checked line by line)
Range −\(10^{-6}\)–0.0514 µs\(^{-1}\) on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine With a standard; α₁ and β₀, β₁ first (p. 112).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF β₁

tof_beta1 · \(\beta_1\) · µs\(^{-1}\)·Å⁴ · refinable

The 1/d\(^{4}\) term of the decay of a TOF peak.

\(\alpha_h = \alpha_0 + \frac{\alpha_1}{d_h} + \frac{\alpha_Q}{\sqrt{d_h}},\quad \beta_h = \beta_0 + \frac{\beta_1}{d_h^4} + \frac{\beta_Q}{d_h^2}\)

Equation as printed in: FullProf_Manual.pdf, p. 112 · TOF_FullProf.pdf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

With Npr = 10 α₀ + α₁ d is a time (µs) mixed with the thermal one as 1/α (the 2003 document's Panel 10); α_Q, β_Q found from alum's .out to its six digits (L341).

FullProf beta1, line 30 (p. 112)
GSAS-II beta-1 (believed from GSAS-II's TOF instrument parameters, not checked line by line)
Range −\(10^{-6}\)–0.0427 µs\(^{-1}\)·Å⁴ on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine With a standard; α₁ and β₀, β₁ first (p. 112).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF β_Q

tof_beta_q · \(\beta_Q\) · µs\(^{-1}\)·Å² · refinable

The 1/d\(^{2}\) term of the decay of a TOF peak.

\(\alpha_h = \alpha_0 + \frac{\alpha_1}{d_h} + \frac{\alpha_Q}{\sqrt{d_h}},\quad \beta_h = \beta_0 + \frac{\beta_1}{d_h^4} + \frac{\beta_Q}{d_h^2}\)

Equation as printed in: FullProf_Manual.pdf, p. 112 · TOF_FullProf.pdf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

With Npr = 10 α₀ + α₁ d is a time (µs) mixed with the thermal one as 1/α (the 2003 document's Panel 10); α_Q, β_Q found from alum's .out to its six digits (L341).

FullProf betaQ, line 30 of FullProf's newer files
GSAS-II beta-q (GSASIIpwd.py L2484)
Range −0.0449–0 µs\(^{-1}\)·Å² on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine With a standard; α₁ and β₀, β₁ first (p. 112).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF thermal α₀

tof_alpha0_thermal · \(\alpha_{0t}\) · µs · refinable

A term of the thermal neutrons' rise or decay time (Hodges), mixed with the epithermal one by the crossover.

\(\frac{1}{\alpha_h} = n\,(\alpha_0 + \alpha_1 d_h) + (1 - n)\left(\alpha_{0t} - \frac{\alpha_{1t}}{d_h}\right)\)

Equation as printed in: FullProf_Manual.pdf, p. 113 · TOF_FullProf.pdf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

The 2003 document's form, 1/α mixed; the manual (p. 112) mixes α itself. FullProf's .out follows the document, to six digits (L341).

FullProf alph0t, line 31 (Npr = 10, p. 113)
GSAS-II none
Range gabriela's TOF pattern alone: 7.387, 27.18, 4.0124, 4.733 µs, µs·Å (α₀ₜ, β₀ₜ, α₁ₜ, β₁ₜ)
Default none: read with Npr = 10
When to refine With a standard over the crossover.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF thermal β₀

tof_beta0_thermal · \(\beta_{0t}\) · µs · refinable

A term of the thermal neutrons' rise or decay time (Hodges), mixed with the epithermal one by the crossover.

\(\frac{1}{\alpha_h} = n\,(\alpha_0 + \alpha_1 d_h) + (1 - n)\left(\alpha_{0t} - \frac{\alpha_{1t}}{d_h}\right)\)

Equation as printed in: FullProf_Manual.pdf, p. 113 · TOF_FullProf.pdf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

The 2003 document's form, 1/α mixed; the manual (p. 112) mixes α itself. FullProf's .out follows the document, to six digits (L341).

FullProf beta0t, line 31 (p. 113)
GSAS-II none
Range gabriela's TOF pattern alone: 7.387, 27.18, 4.0124, 4.733 µs, µs·Å (α₀ₜ, β₀ₜ, α₁ₜ, β₁ₜ)
Default none: read with Npr = 10
When to refine With a standard over the crossover.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF thermal α₁

tof_alpha1_thermal · \(\alpha_{1t}\) · µs·Å · refinable

A term of the thermal neutrons' rise or decay time (Hodges), mixed with the epithermal one by the crossover.

\(\frac{1}{\alpha_h} = n\,(\alpha_0 + \alpha_1 d_h) + (1 - n)\left(\alpha_{0t} - \frac{\alpha_{1t}}{d_h}\right)\)

Equation as printed in: FullProf_Manual.pdf, p. 113 · TOF_FullProf.pdf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

The 2003 document's form, 1/α mixed; the manual (p. 112) mixes α itself. FullProf's .out follows the document, to six digits (L341).

FullProf alph1t, line 31 (p. 113)
GSAS-II none
Range gabriela's TOF pattern alone: 7.387, 27.18, 4.0124, 4.733 µs, µs·Å (α₀ₜ, β₀ₜ, α₁ₜ, β₁ₜ)
Default none: read with Npr = 10
When to refine With a standard over the crossover.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

TOF thermal β₁

tof_beta1_thermal · \(\beta_{1t}\) · µs·Å · refinable

A term of the thermal neutrons' rise or decay time (Hodges), mixed with the epithermal one by the crossover.

\(\frac{1}{\alpha_h} = n\,(\alpha_0 + \alpha_1 d_h) + (1 - n)\left(\alpha_{0t} - \frac{\alpha_{1t}}{d_h}\right)\)

Equation as printed in: FullProf_Manual.pdf, p. 113 · TOF_FullProf.pdf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

The 2003 document's form, 1/α mixed; the manual (p. 112) mixes α itself. FullProf's .out follows the document, to six digits (L341).

FullProf beta1t, line 31 (p. 113)
GSAS-II none
Range gabriela's TOF pattern alone: 7.387, 27.18, 4.0124, 4.733 µs, µs·Å (α₀ₜ, β₀ₜ, α₁ₜ, β₁ₜ)
Default none: read with Npr = 10
When to refine With a standard over the crossover.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Phase.tof

Intensity corrections

Absorption μR

absorption_mur · \(\mu R\) · 1 · refinable

Linear absorption times the radius of a cylindrical sample (or μt of a flat plate in transmission).

\(T_h = \exp\{-(1.7133 - 0.0368 \sin^2\theta)\mu R + (0.0927 + 0.375 \sin^2\theta)(\mu R)^2\}\)

Equation as printed in: FullProf_Manual.pdf, p. 55. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf muR, line 8 (p. 75)
GSAS-II Absorption, μR for Debye–Scherrer by another approximation (GSASIIobj.py L663; GSASIIpwd.py L158–176)
Range 0.35–3.0 in 94 files (median 0.35)
Default 0
When to refine Rarely: calculated from the composition and packing; strongly correlated with the displacement parameters.
Limits Not refined by the engine (core 0.12.0).
Class global (FullProf's relaxation class; believed: not in the manual's list; a property of the sample and pattern)
Largest shift per cycle none
In the core Model.mur

Micro-absorption P₀

microabsorption_p0 · \(P_0\) · 1 · refinable

The constant part of the loss of intensity by surface roughness in Bragg–Brentano geometry.

\(S_r(h) = 1 - P(h),\quad P(h) = P_0 + C_p\,\frac{\tau}{\sin\theta_h}\left(1 - \frac{\tau}{\sin\theta_h}\right)\)

Equation as printed in: FullProf_Manual.pdf, p. 55 · FullProf_Manual.pdf, p. 84. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf P0, line 15, read when More ≠ 0 on line 14 for a Bragg–Brentano X-ray pattern (p. 84)
GSAS-II SurfRoughA, SurfRoughB (GSASIIobj.py L674–675): Suortti's exponential form (GSASIIpwd.py L129–140), not this expression
Range 0 in the three files with line 15 (FP_tests/ce.pcr, ce1.pcr, ce2.pcr)
Default 0
When to refine Rarely: with Cp and \(\tau\), after the structure, for a rough flat sample in Bragg–Brentano geometry; correlated with the displacement parameters.
Limits None.
Class global (FullProf's relaxation class; believed: not in the manual's list; a property of the sample and pattern)
Largest shift per cycle none
In the core Model.microabsorption

Micro-absorption Cp

microabsorption_cp · \(C_p\) · 1 · refinable

The amplitude of the angle-dependent loss of intensity by surface roughness in Bragg–Brentano geometry.

\(P(h) = P_0 + C_p\,\frac{\tau}{\sin\theta_h}\left(1 - \frac{\tau}{\sin\theta_h}\right)\)

Equation as printed in: FullProf_Manual.pdf, p. 55 · FullProf_Manual.pdf, p. 84. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Cp, line 15 (p. 84)
GSAS-II SurfRoughA in Suortti's exponential form (GSASIIpwd.py L129–140), not this expression
Range 1.1988–1.4999 in FP_tests/ce.pcr, ce1.pcr, ce2.pcr (\(\mathrm{CeO_{2}}\), Cu Kα)
Default 0
When to refine Rarely: with \(\tau\), after the structure; strongly correlated with B (both lower the intensity at low angles relative to high).
Limits None.
Class global (FullProf's relaxation class; believed: not in the manual's list; a property of the sample and pattern)
Largest shift per cycle none
Correlated with microabsorption_tau, overall_b, atom_biso: P(h) changes the intensity smoothly with sin \(\theta\), as the Debye–Waller factor exp(−2B \(\mathrm{s}^{2}\)) does: over one pattern the two shapes compensate, and Cp and \(\tau\) compensate each other (\(\tau\)/sin \(\theta\) appears in both factors). Tip: Refine the displacement parameters first; add Cp and \(\tau\) together only for a rough sample, and compare with a smoother one (the manual's refs. 25 and 26 give the limits). FullProf_Manual.pdf, p. 55
In the core Model.microabsorption

Micro-absorption τ

microabsorption_tau · \(\tau\) · 1 · refinable

The roughness parameter of the angle-dependent loss of intensity in Bragg–Brentano geometry, in units of sin \(\theta\).

\(P(h) = P_0 + C_p\,\frac{\tau}{\sin\theta_h}\left(1 - \frac{\tau}{\sin\theta_h}\right)\)

Equation as printed in: FullProf_Manual.pdf, p. 55 · FullProf_Manual.pdf, p. 84. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Tau, line 15 (p. 84)
GSAS-II SurfRoughB in Suortti's exponential form (GSASIIpwd.py L129–140), not this expression
Range 0.1325–0.1451 in FP_tests/ce.pcr, ce1.pcr, ce2.pcr
Default 0
When to refine Rarely: with Cp, after the structure.
Limits None.
Class global (FullProf's relaxation class; believed: not in the manual's list; a property of the sample and pattern)
Largest shift per cycle none
In the core Model.microabsorption

Preferred orientation G₁

po_g1 · \(G_1\) · 1 · refinable

The preferred-orientation strength: March's ratio r (Nor = 1, 1 = none) or the exponential coefficient (Nor = 0, 0 = none).

\(P_h = \frac{1}{m}\sum_{i=1}^{m} \left[G_2 + (1 - G_2)\left((G_1\cos\alpha_i)^2 + \frac{\sin^2\alpha_i}{G_1}\right)^{-3/2}\right]\ (\text{March}),\quad G_2 + (1-G_2)\, e^{-G_1 \alpha_i^2}\ (\text{exponential})\)

Equation as printed in: Dollase_1986.pdf, p. 268 · March_1932.pdf, p. 291 · FullProf_Manual.pdf, p. 54 · FullProf_Manual.pdf, p. 55. Paper: W. A. Dollase (1986). Correction of intensities for preferred orientation in powder diffractometry: application of the March model. J. Appl. Cryst. 19, 267–272. doi:10.1107/S0021889886089458

Dollase sums P over the m symmetry-equivalent planes (eq. 4, p. 268), as FullProf (L042) and GSAS-II (GSASIIstrMath.py lines 3066–3078) do. March–Dollase is Dollase's Table 1, no. 6, the axial case of March (p. 291): the same in FullProf. The exponential is Dollase's no. 5, b + (1 − b)exp(−Gα²); FullProf's eq. 3.31 writes exp(+G1 α²): Convention::preferred_orientation, and a .pcr's Pref1 with Nor = 0 is imported as −Pref1, exactly (L050).

FullProf Pref1, line 30 of the phase (p. 109; meaning p. 112)
GSAS-II MD, the March–Dollase ratio (GSASIIobj.py L649)
Range 1 (none) in all but 3 phases; up to 1.58
Default 1 with Nor = 1, 0 with Nor = 0 (none)
When to refine When the intensities of one zone are systematically off; late.
Limits \(\ge\) \(10^{-3}\) for the March function (undefined at 0); none for the exponential function.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.5 1
In the core Phase.pref

Preferred orientation G₂

po_g2 · \(G_2\) · 1 · refinable

The fraction of the sample without preferred orientation.

\(P_h = G_2 + (1 - G_2)\left[(G_1\cos\alpha_h)^2 + \frac{\sin^2\alpha_h}{G_1}\right]^{-3/2}\)

Equation as printed in: Dollase_1986.pdf, p. 268 · FullProf_Manual.pdf, p. 55. Paper: W. A. Dollase (1986). Correction of intensities for preferred orientation in powder diffractometry: application of the March model. J. Appl. Cryst. 19, 267–272. doi:10.1107/S0021889886089458

FullProf Pref2, line 30 of the phase (p. 109)
GSAS-II none
Range 0 in every file
Default 0
When to refine Rarely, after G1.
Limits 0 to 1 (the untextured fraction).
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.2 1
Correlated with scale_factor: G₂ is the fraction of the sample without preferred orientation, a constant term of P; Dollase found that adding a constant term to a pole-density profile made the refinement diverge through its correlation with the overall scale (1986, p. 270). Tip: Refine G₁ alone; add G₂ only if the fit needs it, with the scale watched. Dollase_1986.pdf, p. 270
In the core Phase.pref

Preferred-orientation axis

po_direction · \(\mathbf{h}_{\mathrm{PO}}\) · reciprocal-lattice components · read, not refined

The preferred-orientation axis; α_h is the angle between it and the scattering vector.

\(\cos\alpha_h = \frac{\mathbf{h}^{T} G^{*} \mathbf{h}_{\mathrm{PO}}}{|\mathbf{h}|\,|\mathbf{h}_{\mathrm{PO}}|}\)

Equation as printed in: FullProf_Manual.pdf, p. 54. Paper: W. A. Dollase (1986). Correction of intensities for preferred orientation in powder diffractometry: application of the March model. J. Appl. Cryst. 19, 267–272. doi:10.1107/S0021889886089458

FullProf Pr1 Pr2 Pr3, line 19 of the phase (p. 89)
GSAS-II MDAxis (GSASIIstrMath.py L3071)
Range [0 0 1] by default; [1 1 0] in Yb2ZrWO8-PO-March
Default [0 0 1]
When to refine Never: chosen.
In the core Phase.pref_direction

March ratio of a preferred-orientation axis

po_axis_ratio · \(r_j\) · 1 · refinable

March's ratio r_j of axis j of a phase textured along several axes: the crystallites with that axis are distributed about the sample's axis by March's density, below 1 for plates, above 1 for needles, 1 for none.

\(P_h = \frac{1}{m}\sum_{i=1}^{m} \sum_j f_j\, \left(r_j^2\cos^2\rho_{ij} + \frac{\sin^2\rho_{ij}}{r_j}\right)^{-3/2}\)

Equation as printed in: Dollase_1986.pdf, p. 268 · March_1932.pdf, p. 291 · Fullprof_News_2003.htm L310–340 · yb_nor2.out L440–445. Paper: W. A. Dollase (1986). Correction of intensities for preferred orientation in powder diffractometry: application of the March model. J. Appl. Cryst. 19, 267–272. doi:10.1107/S0021889886089458

ρ_ij is the angle between axis j and the sample's axis for the i-th of the m reflections equivalent to h: its angle α to h in reflection (Nor = 2, FullProf's G2 does not enter: yb_nor2_g2 has yb_nor2's CORR, L360); in an anvil cell with the beam along the force (Nor = 3), averaged over the cone cos ρ = cos α cos ψ + sin α sin ψ cos φ, ψ = 90° − \(\theta\) (Wright et al. 1996, believed: FullProf's yb_nor3 CORR is up to 3.6 % below it, L360).

FullProf MD-r of each direction's line after line 30-1 (Nor = 2, 3; the News of 12 October 2003)
GSAS-II none: one March–Dollase axis per phase
Range 0.85 and 1.2 in runs/texture/yb_nor2.pcr
Default 1
When to refine As G₁, one axis at a time; with the fractions after the ratios.
Limits \(\ge\) \(10^{-3}\) (undefined at 0).
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.5 1
In the core Phase.texture

Fraction of a preferred-orientation axis

po_axis_fraction · \(f_j\) · 1 · refinable

The fraction f_j of a phase's crystallites oriented about axis j; the fractions sum to 1, and the last is 1 minus the others.

\(f_n = 1 - \sum_{j<n} f_j\)

Equation as printed in: Fullprof_News_2003.htm L310–320

FullProf Fraction of each direction's line after line 30-1 (Nor = 2, 3); the last direction's is not refined
GSAS-II none
Range 0.6 and 0.4 in runs/texture/yb_nor2.pcr
Default 1 for one axis
When to refine After the ratios; a fraction near 0 or 1 makes its axis's ratio undetermined.
Limits 0 to 1.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.2 1
Correlated with po_axis_ratio: An axis's share of P_h is f_j D_j: a small fraction with a strong ratio and a large one with a weak ratio change the intensities alike. Tip: Refine the ratios first, the fractions after them. believed: from the product f_j D_j, not measured
In the core Phase.texture

Steps of the anvil cell's texture integration

po_axis_steps · \(N_\varphi\) · steps · read, not refined

For an anvil cell with the beam along the force: the steps over the azimuth φ of each axis's cone about the scattering vector; 0 for a flat sample in reflection.

\(\bar D_j = \frac{1}{N_\varphi}\sum_{k=1}^{N_\varphi} D\!\left(r_j, \cos\alpha\cos\psi + \sin\alpha\sin\psi\cos\varphi_k\right),\ \varphi_k = \pi\frac{k - 1/2}{N_\varphi}\)

Equation as printed in: Fullprof_News_2003.htm L326–340 · Fullprof_News_2003.htm L408–412

The form is believed (Wright, Nelmes, Belmonte & McMahon 1996, eqs. 4–6, which the News names; the paper is not in manuals/papers): FullProf's yb_nor3 CORR is up to 3.6 % below it, frozen in test texture and listed for Josu (L360).

FullProf NOrstep after NPOD (Nor = 3), 20 when it is not given
GSAS-II none
Range 20 in runs/texture/yb_nor3.pcr
Default 0 (a flat sample)
When to refine Never: chosen.
In the core Phase.texture

TOF extinction

tof_extinction · \(E_x\) · Å⁴/(\(10^{-12}\) cm)² · refinable

Sabine's extinction of a powder in a TOF pattern.

\(x = E_x \left(\frac{\lambda_h F_h}{V}\right)^2,\quad E_h = E_L \cos^2\theta_B + E_B \sin^2\theta_B,\quad E_B = (1 + x)^{-1/2}\)

Equation as printed in: FullProf_Manual.pdf, p. 110. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

Sabine, Von Dreele & Jørgensen (1988), as GSAS: x/(E_x F\(^{2}\) λ²) = 1/V\(^{2}\) on every reflection of arg_si_ext10 and ext100 (L341). E_L = 1 − x/2 + x\(^{2}\)/4 − 5x\(^{3}\)/48 + 7x\(^{4}\)/192 for x \(\le 1\), √(2/πx)(1 − 1/8x − 3/128x\(^{2}\) − 15/1024x\(^{3}\)) above.

FullProf Extinc, Shape1's place on line 26 of a TOF phase (p. 110)
GSAS-II Extinction (Sabine) of the phase's histogram data (believed)
Range 0–265.3 on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine Last, when the strong low-d reflections are calculated too strong.
Limits \(\ge 0\).
Class profile (FullProf's relaxation class; believed: FullProf codes it on the scale's line 26-1 with the profile's Shape1)
Largest shift per cycle none
In the core Phase.tof

TOF absorption

tof_absorption · \(A_1\) · Å⁻¹ · refinable

The sample's absorption per Å of wavelength in a TOF pattern, by the bank's absorption function.

\(x = A_1 \lambda_h:\ \frac{1 - e^{-2x}}{2x}\ \text{(flat plate)},\ e^{-(1.7133 - 0.0368 s^2) x + (0.0927 + 0.375 s^2) x^2}\ \text{(cylinder)},\ e^{-x}\)

Equation as printed in: FullProf_Manual.pdf, p. 113 · FullProf_Manual.pdf, p. 76. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

Each function found from FullProf's CORR (arg_si_abs1, _calc, _abs3: to six digits, 8·\(10^{-6}\) for the cylinder); the manual's Iabscor 3 is e^{−cλ²}, FullProf's e^{−x} (L341). ABS2 is refused: FullProf's two runs with it stopped (L334).

FullProf ABS1, line 33 of a TOF phase (p. 113), by Iabscor of line 8 (p. 76)
GSAS-II Absorption of the histogram's sample parameters (believed)
Range 0–0.149 Å⁻¹ on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default 0
When to refine Late, with the displacement parameters it correlates with.
Limits \(\ge 0\).
Class profile (FullProf's relaxation class; believed: the manual names no class for ABS1)
Largest shift per cycle none
In the core Phase.tof

Background

Background points

background_points · \(b(2\theta_k)\) · counts · refinable

Background heights at chosen angles, interpolated linearly between them.

\(b_i = b_k + (b_{k+1} - b_k)\frac{2\theta_i - 2\theta_k}{2\theta_{k+1} - 2\theta_k}\)

Equation as printed in: FullProf_Manual.pdf, p. 45 · FullProf_Manual.pdf, p. 78. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf POS, BCK, line 10 (p. 78), Nba > 2
GSAS-II Back;n with the 'lin interpolate' function (GSASIIobj.py L639)
Range whatever the data give
Default none
When to refine The heights, after the structure (step 7), or kept fixed.
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background

Background polynomial

background_polynomial · \(B_m\) · counts · refinable

The coefficients of a polynomial background in (2\(\theta\)/Bkpos − 1).

\(b_i = \sum_{m=0}^{11} B_m \left(\frac{2\theta_i}{\mathrm{BKPOS}} - 1\right)^m\)

Equation as printed in: FullProf_Manual.pdf, pp. 45–46. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf B0–B11, line 17 (p. 85), Nba = 0
GSAS-II Back;n with 'chebyschev' or other functions (GSASIIobj.py L639)
Range whatever the data give
Default 0
When to refine B0 early (step 2), the others late (step 7).
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background

Background origin

background_origin · \(\mathrm{BKPOS}\) · deg 2\(\theta\) · read, not refined

The origin of the polynomial background.

\(b_i = \sum_{m} B_m \left(\frac{2\theta_i}{\mathrm{BKPOS}} - 1\right)^m\)

Equation as printed in: FullProf_Manual.pdf, p. 46 · FullProf_Manual.pdf, p. 75. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Bkpos, line 8 (p. 75)
GSAS-II none
Range the middle of the pattern, usually
Default none: read
When to refine Never.
In the core Model.background

Background Chebyshev series

background_chebyshev · \(c_m\) · counts · refinable

The coefficients of a Chebyshev series over the data range (Nba = −5; not in the 2001 manual, since June 2011).

\(b_i = \sum_{m=0}^{23} c_m T_m(x_i),\quad x_i = 2\frac{2\theta_i - 2\theta_{\min}}{2\theta_{\max} - 2\theta_{\min}} - 1\)

Equation as printed in: FullProf_News_2011.htm L129–137 · Cocus-asym.pcr L25–33

FullProf where the Fourier coefficients go (line 17), Nba = −5
GSAS-II Back;n with 'chebyschev' (GSASIIobj.py L639)
Range whatever the data give
Default 0
When to refine c0 early, the others late (step 7).
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
Correlated with background_chebyshev: The Chebyshev polynomials T_k are independent over their whole range, from the first point to the last, and they differ most near its ends. When the points fitted do not reach an end (an excluded region at the start, or a range wider than the data) the terms become nearly dependent: Egypt, with 5–6.7° of its 5–75° excluded, has its fifteen terms correlated up to 0.996 (L076; numpy gives 0.995 for the same points). Tip: Refine fewer terms, or let the background function span only the points fitted; for a short or interrupted range, background points interpolated by the user are steadier (manual p. 14, step 2). FullProf_News_2011.htm L129–137 · FullProf_Manual.pdf, p. 14
In the core Model.background

Background Fourier series

background_fourier · \(B_j\) · counts · refinable

The coefficients of a Fourier cosine series in 2\(\theta\) (Nba = −4).

\(b_i = \sum_{j=0}^{11} B_j \cos(j\, 2\theta_i)\)

Equation as printed in: FullProf_Manual.pdf, pp. 45–46 · Fullprof_News_2001.htm L513–554. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf line 17, Nba = −4 (the News; the 2001 manual gives no Nba value)
GSAS-II Back;n with 'cosine' (GSASIIobj.py L639)
Range whatever the data give
Default 0
When to refine Late (step 7).
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background

Background Debye-like amplitude

background_debye_amplitude · \(A_j\) · counts · refinable

The amplitude of a Debye-like term of the background: the diffuse scattering of a pair of atoms at distance r_j in an amorphous part or a liquid (FullProf's Nba = −1).

\(b_i = \sum_m B_m \left(\frac{2\theta_i}{\mathrm{BKPOS}} - 1\right)^m + \sum_j A_j \frac{\sin(Q_i r_j)}{Q_i r_j},\quad Q_i = \frac{4\pi\sin\theta_i}{\lambda_1}\)

Equation as printed in: FullProf_Manual.pdf, p. 45 · nac_3t2_calc.prf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf BC_j, the line after the six coefficients of line 17 ("Additional background coefficients"), Nba = −1
GSAS-II DebyeA;n (GSASIIobj.py L677), with a damping exp(−U Q\(^{2}\)) and a factor ff (GSASIIpwd.py L1083)
Range −37.5 to 33.0 in FP_tests/nac_3t2.pcr (3T2, \(\mathrm{Na_{2}Ca_{3}Al_{2}F_{14}}\))
Default 0
When to refine With the polynomial, after the structure, when an amorphous part or a liquid gives the background its waves.
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background_terms

Background Debye-like distance

background_debye_distance · \(r_j\) · Å · refinable

The distance of a Debye-like term of the background, the separation of the pair of atoms whose diffuse scattering it is.

\(A_j \frac{\sin(Q_i r_j)}{Q_i r_j}\)

Equation as printed in: FullProf_Manual.pdf, p. 45 · nac_3t2_calc.prf. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf r_j, the line pair after the amplitudes', Nba = −1
GSAS-II DebyeR;n (GSASIIobj.py L678)
Range 1.40–4.95 Å in FP_tests/nac_3t2.pcr
Default none: given
When to refine Rarely, and only with its amplitude fixed: a distance is a bond length of the amorphous part, best known from its chemistry.
Limits r > 0.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background_terms

Background inverse powers

background_inverse_power · \(c_j\) · counts·deg^j · refinable

The coefficients of 1/2\(\theta\), 1/2\(\theta\)² and 1/2\(\theta\)³ added to a polynomial of nine coefficients (FullProf's Nba = −3), for the steep background at low angles.

\(b_i = \sum_{m=0}^{8} B_m \left(\frac{2\theta_i}{\mathrm{BKPOS}} - 1\right)^m + \sum_{j=1}^{3} c_j (2\theta_i)^{-j}\)

Equation as printed in: Fullprof_News_2003.htm L963 · y2o3_poly12_b10.prf · y2o3_poly12_b12.prf

FullProf the 10th to 12th coefficients of line 17, Nba = −3 (News of 28 July 2003, whose formula is an image that is lost: the form read from FullProf's runs, 2\(\theta\) in degrees, L353)
GSAS-II none: GSAS-II's 'chebyschev-1' and 'cosine' series have no inverse powers (GSASIIpwd.py L978)
Range whatever the data give
Default 0
When to refine Late (step 7), for a pattern that starts at low angle with a background falling steeply.
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background_terms

Background profile coefficient

background_profile · \(k_n\) · 1 · refinable

The coefficient of a background profile read from a file (an empty holder's pattern, a calculated thermal diffuse scattering), added to the background function.

\(b_i = f(2\theta_i) + \sum_n k_n\, P_n(2\theta_i)\)

Equation as printed in: Fullprof_News_2003.htm L1149–1153 · y2o3_more2_two.out

FullProf MORE = 2 or 3 on line 14: the number of profiles and their coefficients, then their codewords; profile n from {data}_n.bac
GSAS-II a fixed background histogram with its multiplier (fixback, GSASIIpwd.py L978)
Range 0.5 and 2 in runs/background_terms/y2o3_more2_two.pcr
Default 1
When to refine With the scale factors, when the profile's share of the pattern is not known.
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background_terms

Background file scale b₁

background_file_scale · \(b_1\) · 1 · refinable

The factor on a background read from a file (FullProf's Nba = 1); FullProf reads 0 as 1.

\(b_i = b_1\,B\left[(1 + b_3)\,2\theta_i + b_4\right] + b_2\)

Equation as printed in: FullProf_Manual.pdf, p. 46 · y2o3_bac_b3b4.out

FullProf b1 … b4, line 17 with Nba = 1 (manual eq. 3.6, p. 46): the .bac file's background CODFIL.bac moved and scaled; the .out writes Back(2\(\theta\)) = a·BackRead[(1 + c)2\(\theta\) + d] + b
GSAS-II none: GSAS-II's fixed background has a multiplier only (fixback, GSASIIpwd.py L978)
Range 0.8 in runs/background_terms/y2o3_bac_b1b2.pcr
Default 1
When to refine When the file's background is right in shape and off in size or place; b1 and b2 with the scale factors, b3 and b4 late.
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background_terms

Background file offset b₂

background_file_offset · \(b_2\) · counts · refinable

A constant added to a background read from a file (Nba = 1).

\(b_i = b_1\,B\left[(1 + b_3)\,2\theta_i + b_4\right] + b_2\)

Equation as printed in: FullProf_Manual.pdf, p. 46 · y2o3_bac_b3b4.out

FullProf b1 … b4, line 17 with Nba = 1 (manual eq. 3.6, p. 46): the .bac file's background CODFIL.bac moved and scaled; the .out writes Back(2\(\theta\)) = a·BackRead[(1 + c)2\(\theta\) + d] + b
GSAS-II none: GSAS-II's fixed background has a multiplier only (fixback, GSASIIpwd.py L978)
Range 5 in y2o3_bac_b1b2.pcr
Default 0
When to refine When the file's background is right in shape and off in size or place; b1 and b2 with the scale factors, b3 and b4 late.
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background_terms

Background file stretch b₃

background_file_stretch · \(b_3\) · 1 · refinable

The stretch of the angle a background read from a file is read at, (1 + b₃)2\(\theta\) (Nba = 1).

\(b_i = b_1\,B\left[(1 + b_3)\,2\theta_i + b_4\right] + b_2\)

Equation as printed in: FullProf_Manual.pdf, p. 46 · y2o3_bac_b3b4.out

FullProf b1 … b4, line 17 with Nba = 1 (manual eq. 3.6, p. 46): the .bac file's background CODFIL.bac moved and scaled; the .out writes Back(2\(\theta\)) = a·BackRead[(1 + c)2\(\theta\) + d] + b
GSAS-II none: GSAS-II's fixed background has a multiplier only (fixback, GSASIIpwd.py L978)
Range 0.01 in y2o3_bac_b3b4.pcr
Default 0
When to refine When the file's background is right in shape and off in size or place; b1 and b2 with the scale factors, b3 and b4 late.
Limits Above −1 (at −1 the file is read at one angle).
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background_terms

Background file shift b₄

background_file_shift · \(b_4\) · deg · refinable

The shift of the angle a background read from a file is read at, (1 + b₃)2\(\theta\) + b₄ (Nba = 1).

\(b_i = b_1\,B\left[(1 + b_3)\,2\theta_i + b_4\right] + b_2\)

Equation as printed in: FullProf_Manual.pdf, p. 46 · y2o3_bac_b3b4.out

FullProf b1 … b4, line 17 with Nba = 1 (manual eq. 3.6, p. 46): the .bac file's background CODFIL.bac moved and scaled; the .out writes Back(2\(\theta\)) = a·BackRead[(1 + c)2\(\theta\) + d] + b
GSAS-II none: GSAS-II's fixed background has a multiplier only (fixback, GSASIIpwd.py L978)
Range 0.5 in y2o3_bac_b3b4.pcr
Default 0
When to refine When the file's background is right in shape and off in size or place; b1 and b2 with the scale factors, b3 and b4 late.
Limits None.
Class global (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle none
In the core Model.background_terms

Phase and structure

Scale factor

scale_factor · \(S_\phi\) · arbitrary · refinable

The factor that brings the phase's calculated intensities to the observed counts.

\(y_{ci} = \sum_\phi S_\phi \sum_h I_{\phi h}\, \Omega(2\theta_i - 2\theta_{\phi h}) + b_i\)

Equation as printed in: FullProf_Manual.pdf, p. 41. Paper: H. M. Rietveld (1969). A profile refinement method for nuclear and magnetic structures. J. Appl. Cryst. 2, 65–71. doi:10.1107/S0021889869006558

A .pcr's X-ray scale is doubled on import (Ilo = 0, 1, 4): FullProf's Lp is twice the manual's eq. 3.26 (L047, L050).

FullProf Scale, line 26 of the phase (p. 108)
GSAS-II Scale, the phase fraction (p:h:Scale) or the histogram scale (:h:Scale) (GSASIIobj.py L618)
Range \(10^{-4}\) to 1.3·\(10^{4}\) (median 1.47): depends on the counts
Default none: read
When to refine First (manual p. 14, step 1).
Limits \(\ge 0\).
Class profile (FullProf's relaxation class; measured: R_pr = 0.5 halves the scale's shift and leaves its esd (manuals/fullprof/runs/shift_control/r05.out against m10.out, FullProf 8.20; L107); the manual's list names no class for it)
Largest shift per cycle none
Correlated with overall_b, atom_occupancy, atom_biso: The scale multiplies every reflection of the phase; the occupancies multiply the scattering of their sites, and the displacement parameters lower it by exp(−B \(\mathrm{s}^{2}\)), which at low sin \(\theta\)/λ is close to a constant factor (manual eqs. 3.44–3.46). Together they can trade intensity with the scale. Tip: Refine the scale first; occupancies only with some sites held full, and the overall B before individual B's (manual p. 14, steps 1, 3, 5, 6). FullProf_Manual.pdf, p. 58 · FullProf_Manual.pdf, p. 14
In the core Phase.scale

Phase mass factor ATZ

qpa_atz · \(ATZ_\phi\) · g/mol · read, not refined

The phase's mass per cell over its absorption contrast, which turns its scale factor into a weight fraction.

\(ATZ_\phi = \frac{Z_\phi M_\phi f_\phi^2}{t_\phi},\quad W_\phi = \frac{S_\phi\, ATZ_\phi V_\phi / t_\phi}{\sum_\psi S_\psi\, ATZ_\psi V_\psi / t_\psi}\)

Equation as printed in: FullProf_Manual.pdf, p. 91 · FullProf_Manual.pdf, p. 31. Paper: R. J. Hill & C. J. Howard (1987). Quantitative phase analysis from neutron powder diffraction data using the Rietveld method. J. Appl. Cryst. 20, 467–474

The core divides by the Brindley coefficient once more, as the manual's p. 31 writes W; every phase of the material has t = 1, so whether FullProf's ATZ already holds t is not checked.

FullProf ATZ, line 19 of the phase (p. 91)
GSAS-II not checked: GSAS-II's weight fractions were not read
Range 0 to 2.5·\(10^{7}\) (median 927; 426 of 453 phases set it)
Default 0: no weight fraction
When to refine Never: computed from the formula (FullProf checks it and prints the value it calculates).
In the core Phase.atz

Brindley coefficient

brindley_coefficient · \(t_\phi\) · 1 · read, not refined

Brindley's particle absorption contrast factor of the phase, for microabsorption in quantitative analysis.

\(t_\phi = \frac{1}{V_\phi}\int \exp\{-(\mu_\phi - \bar\mu)x\}\, dV_\phi\)

Equation as printed in: FullProf_Manual.pdf, p. 31. Paper: R. J. Hill & C. J. Howard (1987). Quantitative phase analysis from neutron powder diffraction data using the Rietveld method. J. Appl. Cryst. 20, 467–474

FullProf Brind, line 19-1 of the phase (p. 93)
GSAS-II not checked
Range 1 in all 154 phases that give it
Default 1
When to refine Never: tabulated from (μ_φ − μ̄)R (manual pp. 31–32).
In the core Phase.brindley

Overall displacement B

overall_b · \(B_{\mathrm{ov}}\) · Ų · refinable

An isotropic displacement common to all atoms of the phase, applied to the intensities.

\(I_h \propto |F_h|^2 \exp(-2 B_{\mathrm{ov}} s^2),\quad s = \frac{\sin\theta}{\lambda}\)

Equation as printed in: FullProf_Manual.pdf, p. 58. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Bov, line 26 of the phase (p. 108)
GSAS-II none: displacement parameters per atom
Range −0.21 to 3.57 (median 0.12)
Default 0
When to refine Early with the positions (step 3), then turned into individual Biso (step 6).
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 1 Ų
Correlated with atom_biso: The overall factor exp(−2B_ov \(\mathrm{s}^{2}\)) multiplies |F|², and adding δ to the B of every atom of the phase multiplies |F|² by exp(−2δ \(\mathrm{s}^{2}\)): with every atom's B refined, the overall B adds nothing the atoms' B's do not already do. Tip: Refine the overall B, or the atoms' B's, not both (manual p. 14, step 6: the overall factor is turned into individual ones). FullProf_Manual.pdf, p. 58 · FullProf_Manual.pdf, p. 14
In the core Phase.bov

Cell a

cell_a · \(a\) · Å · refinable

The length of the first cell edge.

\(\frac{1}{d_{hkl}^2} = \mathbf{h}^{T} G^{*} \mathbf{h}\)

Equation as printed in: FullProf_Manual.pdf, p. 107. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf a, line 29 of the phase (p. 107)
GSAS-II a, derived from the refined reciprocal metric A0–A5 (GSASIIobj.py L613)
Range 2.85–40.6 Å over all edges (median 5.76)
Default none: read
When to refine Early (step 2), constrained by the crystal system.
Limits \(\ge\) \(10^{-3}\) Å.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.1 Å
Correlated with zero_shift, sample_displacement: A change of the cell moves each peak by −2 tan \(\theta\) Δd/d (Bragg's law); the zero moves every peak alike and the displacement as cos \(\theta\). Over a short angular range these shifts are nearly proportional. Tip: Take the zero from a standard measured on the instrument when the range is short (manual p. 14), or refine the cell and the zero over a wide range of angles. FullProf_Manual.pdf, p. 56 · FullProf_Manual.pdf, p. 14
In the core Phase.cell

Cell b

cell_b · \(b\) · Å · refinable

The length of the second cell edge.

\(\frac{1}{d_{hkl}^2} = \mathbf{h}^{T} G^{*} \mathbf{h}\)

Equation as printed in: FullProf_Manual.pdf, p. 107. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf b, line 29 of the phase (p. 107)
GSAS-II b (GSASIIobj.py L613)
Range as a
Default none: read
When to refine Early (step 2).
Limits \(\ge\) \(10^{-3}\) Å.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.1 Å
Correlated with zero_shift, sample_displacement: A change of the cell moves each peak by −2 tan \(\theta\) Δd/d (Bragg's law); the zero moves every peak alike and the displacement as cos \(\theta\). Over a short angular range these shifts are nearly proportional. Tip: Take the zero from a standard measured on the instrument when the range is short (manual p. 14), or refine the cell and the zero over a wide range of angles. FullProf_Manual.pdf, p. 56 · FullProf_Manual.pdf, p. 14
In the core Phase.cell

Cell c

cell_c · \(c\) · Å · refinable

The length of the third cell edge.

\(\frac{1}{d_{hkl}^2} = \mathbf{h}^{T} G^{*} \mathbf{h}\)

Equation as printed in: FullProf_Manual.pdf, p. 107. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf c, line 29 of the phase (p. 107)
GSAS-II c (GSASIIobj.py L613)
Range as a
Default none: read
When to refine Early (step 2).
Limits \(\ge\) \(10^{-3}\) Å.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.1 Å
Correlated with zero_shift, sample_displacement: A change of the cell moves each peak by −2 tan \(\theta\) Δd/d (Bragg's law); the zero moves every peak alike and the displacement as cos \(\theta\). Over a short angular range these shifts are nearly proportional. Tip: Take the zero from a standard measured on the instrument when the range is short (manual p. 14), or refine the cell and the zero over a wide range of angles. FullProf_Manual.pdf, p. 56 · FullProf_Manual.pdf, p. 14
In the core Phase.cell

Cell α

cell_alpha · \(\alpha\) · deg · refinable

The angle between the b and c edges.

\(\frac{1}{d_{hkl}^2} = \mathbf{h}^{T} G^{*} \mathbf{h}\)

Equation as printed in: FullProf_Manual.pdf, p. 107. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf alpha, line 29 of the phase (p. 107)
GSAS-II α (GSASIIobj.py L614)
Range 55.3–124.4° over all angles (90° in nine of ten)
Default none: read
When to refine Early (step 2), when the system allows it.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 1 deg
In the core Phase.cell

Cell β

cell_beta · \(\beta\) · deg · refinable

The angle between the a and c edges.

\(\frac{1}{d_{hkl}^2} = \mathbf{h}^{T} G^{*} \mathbf{h}\)

Equation as printed in: FullProf_Manual.pdf, p. 107. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf beta, line 29 of the phase (p. 107)
GSAS-II β (GSASIIobj.py L615)
Range as α
Default none: read
When to refine Early (step 2), when the system allows it.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 1 deg
In the core Phase.cell

Cell γ

cell_gamma · \(\gamma\) · deg · refinable

The angle between the a and b edges.

\(\frac{1}{d_{hkl}^2} = \mathbf{h}^{T} G^{*} \mathbf{h}\)

Equation as printed in: FullProf_Manual.pdf, p. 107. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf gamma, line 29 of the phase (p. 107)
GSAS-II \(\gamma\) (GSASIIobj.py L616)
Range as α
Default none: read
When to refine Early (step 2), when the system allows it.
Limits None.
Class profile (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 1 deg
In the core Phase.cell

Atom position

atom_position · \(x_j, y_j, z_j\) · fraction of the cell edge · refinable

The fractional coordinates of an atom; the structure factor sums over its images by the space group.

\(F_h = \sum_j f_j\, \mathrm{Occ}_j\, T_j \sum_{s} \exp\{2\pi i\, \mathbf{h}\cdot(R_s \mathbf{x}_j + \mathbf{t}_s)\}\)

Equation as printed in: FullProf_Manual.pdf, p. 41 · FullProf_Manual.pdf, p. 100. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf X, Y, Z, line 25-1 (p. 100)
GSAS-II Ax, Ay, Az (GSASIIobj.py L624)
Range 0–1
Default none: read
When to refine After the scale, cell and zero (step 3), within the site's constraints.
Limits None.
Class atomic (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.05 fraction of the cell edge
In the core Atom.x

Isotropic displacement B

atom_biso · \(B_j\) · Ų · refinable

The isotropic displacement (Debye–Waller) parameter of an atom; B = 8π²U.

\(T_j = \exp(-B_j s^2),\quad s = \frac{\sin\theta}{\lambda}\)

Equation as printed in: FullProf_Manual.pdf, p. 100. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Biso, line 25-1 (p. 100)
GSAS-II AUiso, as U in Ų (GSASIIobj.py L625)
Range −1.97 to 6.17 (median 0.50)
Default 0
When to refine After the overall B (step 6).
Limits \(\ge 0\).
Class atomic (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 1 Ų
In the core Atom.biso

Occupancy

atom_occupancy · \(\mathrm{Occ}_j\) · 1 · refinable

FullProf's occupancy: the chemical occupancy times the site's multiplicity over the general position's.

\(\mathrm{Occ}_j = o_j\, \frac{m_j}{M}\)

Equation as printed in: FullProf_Manual.pdf, p. 100. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf Occ, line 25-1 (p. 100)
GSAS-II Afrac, the chemical occupancy o_j itself (GSASIIobj.py L627)
Range 0.25–1 (median 1); up to 9 in files that scale it
Default 1
When to refine When required, after the positions (step 5); correlated with B.
Limits 0 to a full site: Occ \(\le\) m/M (o \(\le 1\); W12, L107), where the structure's occupancies follow that convention (or the primitive cell's, m/c); none above where the file scales them otherwise.
Class atomic (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.2 1
Correlated with atom_biso: Both lower the scattering of a site: the occupancy by a constant factor, the displacement parameter by exp(−B \(\mathrm{s}^{2}\)), which differs from a constant only at high sin \(\theta\)/λ. With data to a short range of sin \(\theta\)/λ they trade one for the other. Tip: Refine occupancies late and one at a time; hold the B's of chemically similar atoms equal (manual p. 14, step 5 and its last paragraph). FullProf_Manual.pdf, p. 58 · FullProf_Manual.pdf, p. 14
In the core Atom.occ

Anisotropic displacement β

atom_betas · \(\beta_{11} \dots \beta_{23}\) · 1 · refinable

The anisotropic displacement of an atom, as FullProf's betas.

\(T_j = \exp\{-(\beta_{11}h^2 + \beta_{22}k^2 + \beta_{33}l^2 + 2\beta_{12}hk + 2\beta_{13}hl + 2\beta_{23}kl)\}\)

Equation as printed in: FullProf_Manual.pdf, p. 100. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf B11–B23, line 25-3 (p. 100), N_t = 2
GSAS-II AU11–AU23, as U_ij in Ų (GSASIIobj.py L626)
Range β_ii 0.0015–0.026 in 141 atoms
Default none (isotropic)
When to refine Last of the structure, if the data allow (step 8).
Limits None.
Class anisotropic (FullProf's relaxation class; FullProf_Manual.pdf, p. 77)
Largest shift per cycle 0.01 1
In the core Atom.beta

Symmetry-mode amplitude

mode_amplitude · \(Q_m\) · Å · refinable

The amplitude of a symmetry-adapted distortion mode: the atoms sit at the reference (parent) structure's positions plus Σ_m Q_m c_m V_m, refined in place of the coordinates (R29); the modes of one irrep make its amplitude A = √(Σ Q\(^{2}\)) and polarisation vector Q/A.

\(\mathbf{r}_j = \mathbf{r}^0_j + \sum_m Q_m\, c_m\, \mathbf{V}_{mj},\qquad A_{\Gamma} = \Big(\sum_{m \in \Gamma} Q_m^2\Big)^{1/2}\)

Equation as printed in: FullProf-Tutorial-Symmetry-Modes.pdf, p. 4 · nb5132.md L255. Paper: J. Rodríguez-Carvajal, notes on symmetry modes in FullProf (fp2k.inf, 29 August 2008 – 20 May 2010), reproduced in the tutorial 'AMPLIMODES and FullProf: symmetry modes crystallography' (manuals/fullprof/7-FullProf-Tutorial-SymmetryModes/FullProf-Tutorial-Symmetry-Modes.pdf)

FullProf A_MODES lines of a Jbt = 6 phase: name, value, codeword (fp2k.inf, 29 August 2008)
GSAS-II the mode variables of an ISODISTORT CIF, refined through constraints (GSASIIstrIO.py L305)
Range 1.11 Å for CaTiO3's R4+ tilt in FullProf's tutorial (7-FullProf-Tutorial-SymmetryModes, CaTiO3ref.pcr)
Default 0 (the reference structure)
When to refine In place of the coordinates, after the scale, cell and profile: the primary irrep's modes first, the secondary ones then (the course's exercises).
Limits |Q| \(\le\) Max_Amplitude when the file gives one; none otherwise.
Class atomic (FullProf's relaxation class; believed: the amplitudes are refined in place of the coordinates, which are atomic)
Largest shift per cycle 0.2 Å
In the core Phase.modes

Rigid group origin

rigid_origin · \(X_0, Y_0, Z_0\) · fraction of the cell edge · refinable

Where a rigid group's own frame sits in the cell: its atoms are r_C = R(\(\theta\), φ, \(\chi\)) r_m + M X_0 in the crystal's Cartesian frame (x ∥ a, z ∥ c*); refined in place of the atoms' coordinates (P41). A satellite group's origin is its parent's atom N1.

\(\mathbf{x}_j = \mathbf{X}_0 + M^{-1} R(\theta,\phi,\chi)\, \mathbf{r}^{m}_j\)

Equation as printed in: FullProf-Restraints-RigidBodies.pdf, p. 8 · FullProf_Manual.pdf, p. 34. Paper: J. Rodríguez-Carvajal, restraints and rigid bodies in FullProf (manuals/fullprof/docs/FullProf-Restraints-RigidBodies.pdf), after V. Rodríguez's STRMOD, 'General Rigid-Body-Constraints/TLS Subroutine' (FullProf's manual, pp. 32–36)

FullProf X0, Y0, Z0 (P12–P14) of a group's first atom, line 25-3 of a Jbt = 4 phase (p. 100)
GSAS-II the rigid body's origin, RBO (GSASIImath.py L1398, not in the repository)
Range 0–1
Default none: read
When to refine After the orientation, when the group sits on no special position.
Limits None.
Class atomic (FullProf's relaxation class; believed: the group's values are refined in place of its atoms' coordinates)
Largest shift per cycle 0.05 fraction of the cell edge
In the core Phase.rigid

Rigid group orientation

rigid_orientation · \(\theta, \phi, \chi\) · deg · refinable

The Euler angles that turn a rigid group's own frame into the crystal's: R = R_z(φ) R_y(\(\theta\)) R_z(\(\chi\)). A satellite's \(\theta\) and φ are those of its bond from its parent; its \(\chi\) is its own.

\(R(\theta,\phi,\chi) = R_z(\phi)\, R_y(\theta)\, R_z(\chi)\)

Equation as printed in: FullProf-Restraints-RigidBodies.pdf, p. 8 · FullProf_Manual.pdf, p. 34. Paper: J. Rodríguez-Carvajal, restraints and rigid bodies in FullProf (manuals/fullprof/docs/FullProf-Restraints-RigidBodies.pdf), after V. Rodríguez's STRMOD, 'General Rigid-Body-Constraints/TLS Subroutine' (FullProf's manual, pp. 32–36)

FullProf THETA, PHI (P7, P8, line 25-1) and CHI (P15, line 25-3) of a group's first atom; in radians when DEG = 0, the core keeping degrees
GSAS-II the rigid body's orientation as a quaternion (GSASIImath.py L1398, not in the repository)
Range \(\theta\) −180–180, φ and \(\chi\) 0–360
Default none: read
When to refine First of a group's values (FullProf's tutorials: the orientation, then the origin, then the torsions).
Limits None.
Class atomic (FullProf's relaxation class; believed: the group's values are refined in place of its atoms' coordinates)
Largest shift per cycle 2.0 deg
In the core Phase.rigid

Rigid group internal length

rigid_length · \(r, \rho, d, x_m, y_m, z_m\) · Å · refinable

A length among a group atom's internal coordinates: the radius of spherical coordinates, ρ and z of cylindrical ones, x, y, z of Cartesian ones, the distance to N1 of a Z-matrix.

\(\mathbf{r}^{m} = r(\sin\theta\cos\phi, \sin\theta\sin\phi, \cos\theta)\ \text{(spherical)},\ (\rho\cos\phi, \rho\sin\phi, z)\ \text{(cylindrical)}\)

Equation as printed in: FullProf-Restraints-RigidBodies.pdf, p. 5 · FullProf-Restraints-RigidBodies.pdf, p. 6. Paper: J. Rodríguez-Carvajal, restraints and rigid bodies in FullProf (manuals/fullprof/docs/FullProf-Restraints-RigidBodies.pdf), after V. Rodríguez's STRMOD, 'General Rigid-Body-Constraints/TLS Subroutine' (FullProf's manual, pp. 32–36)

FullProf P9–P11 of a group atom, line 25-3 (KIND 0 spherical, 1 Cartesian, 2 cylindrical, 3 Z-matrix)
GSAS-II the rigid body's vectors and residue bonds (not in the repository)
Range a bond, 0.9–2.5 Å
Default none: read
When to refine Seldom: a rigid group's shape is usually fixed; a Z-matrix's torsions are refined before its lengths.
Limits None.
Class atomic (FullProf's relaxation class; believed: the group's values are refined in place of its atoms' coordinates)
Largest shift per cycle 0.05 Å
In the core Phase.rigid

Rigid group internal angle

rigid_angle · \(\theta_m, \phi_m, \alpha, \tau\) · deg · refinable

An angle among a group atom's internal coordinates: \(\theta\) and φ of spherical ones, φ of cylindrical ones, the bond angle to N2 and the torsion to N3 of a Z-matrix (FullProf's sense, the opposite of IUPAC's; the third atom on the +y side of the xy plane).

\(\text{Z-matrix: } |\mathbf{r}_j - \mathbf{r}_{N1}| = d,\ \angle(N2, N1, j) = \alpha,\ \text{torsion}(N3, N2, N1, j) = -\tau\)

Equation as printed in: FullProf-Restraints-RigidBodies.pdf, p. 6 · FullProf-Restraints-RigidBodies.pdf, p. 11. Paper: J. Rodríguez-Carvajal, restraints and rigid bodies in FullProf (manuals/fullprof/docs/FullProf-Restraints-RigidBodies.pdf), after V. Rodríguez's STRMOD, 'General Rigid-Body-Constraints/TLS Subroutine' (FullProf's manual, pp. 32–36)

FullProf P10, P11 of a group atom, line 25-3; a Z-matrix atom's N1 N2 N3 in P6–P8 of its line 25-1
GSAS-II the residue rigid body's torsions (not in the repository)
Range 0–360
Default none: read
When to refine A Z-matrix's torsions after the orientation and origin (FullProf's simulated annealing examples).
Limits None.
Class atomic (FullProf's relaxation class; believed: the group's values are refined in place of its atoms' coordinates)
Largest shift per cycle 2.0 deg
In the core Phase.rigid

TLS translation tensor

rigid_tls_t · \(T_{ij}\) · Ų · refinable

The rigid group's translational displacement (Schomaker & Trueblood 1968): T11 T22 T33 T12 T13 T23 in the crystal's Cartesian frame (x along a, z along c*); with L and S it gives every atom of the group and of its satellites an anisotropic U (L367).

\(U = T + A L A^{T} + A S + S^{T} A^{T},\ A = \begin{pmatrix} 0 & z & -y \\ -z & 0 & x \\ y & -x & 0 \end{pmatrix},\ \beta = 2\pi^2 M^{-1} U M^{-T}\)

Equation as printed in: FullProf-Restraints-RigidBodies.pdf, p. 8 · FullProf_Manual.pdf, p. 38. Paper: J. Rodríguez-Carvajal, restraints and rigid bodies in FullProf (manuals/fullprof/docs/FullProf-Restraints-RigidBodies.pdf), after V. Rodríguez's STRMOD, 'General Rigid-Body-Constraints/TLS Subroutine' (FullProf's manual, pp. 32–36)

FullProf t11 … t23 of the phase's Furth lines (LINE 43) with P6 = 5.0x
GSAS-II the rigid body's TLS (not in the repository)
Range positive definite; 0.005–0.05 Ų for molecules at room temperature (believed)
Default none: read
When to refine With L and S after the group's origin and orientation, with the codewords the site symmetry asks (FullProf's manual p. 38: the site's, not the molecule's).
Limits None.
Class atomic (FullProf's relaxation class; believed: displacements of the group's atoms)
Largest shift per cycle 0.01 Ų
In the core Phase.rigid

TLS libration tensor

rigid_tls_l · \(L_{ij}\) · rad\(^{2}\) · refinable

The rigid group's libration about its centre: L11 L22 L33 L12 L13 L23 in the crystal's Cartesian frame, in rad\(^{2}\) as FullProf's .pcr holds them (its .out prints deg\(^{2}\), as the results file does).

\(U = T + A L A^{T} + A S + S^{T} A^{T}\)

Equation as printed in: FullProf-Restraints-RigidBodies.pdf, p. 8 · FullProf_Manual.pdf, p. 38. Paper: J. Rodríguez-Carvajal, restraints and rigid bodies in FullProf (manuals/fullprof/docs/FullProf-Restraints-RigidBodies.pdf), after V. Rodríguez's STRMOD, 'General Rigid-Body-Constraints/TLS Subroutine' (FullProf's manual, pp. 32–36)

FullProf l11 … l23 of the phase's Furth lines (LINE 43) with P6 = 5.0x
GSAS-II the rigid body's TLS (not in the repository)
Range positive definite; up to about 0.02 rad\(^{2}\) (believed)
Default none: read
When to refine With T, after the group's origin and orientation.
Limits None.
Class atomic (FullProf's relaxation class; believed: displacements of the group's atoms)
Largest shift per cycle 0.005 rad\(^{2}\)
In the core Phase.rigid

TLS screw tensor

rigid_tls_s · \(S_{ij}\) · Å·rad · refinable

The correlation of the group's translation and libration: S11 S22 S33 S12 S13 S23, then S21 S31 S32 (S is not symmetric); its trace is not determined by the data, so one of S11, S22, S33 is tied to the others (urea's s22 = −s11). FullProf's .out prints Å·deg, as the results file does.

\(U = T + A L A^{T} + A S + S^{T} A^{T}\)

Equation as printed in: FullProf-Restraints-RigidBodies.pdf, p. 8 · FullProf_Manual.pdf, p. 38. Paper: J. Rodríguez-Carvajal, restraints and rigid bodies in FullProf (manuals/fullprof/docs/FullProf-Restraints-RigidBodies.pdf), after V. Rodríguez's STRMOD, 'General Rigid-Body-Constraints/TLS Subroutine' (FullProf's manual, pp. 32–36)

FullProf s11 … s32 of the phase's Furth lines (LINE 43, 21 of them) with P6 = 5.0x
GSAS-II the rigid body's TLS (not in the repository)
Range |S_ij| below about 0.01 Å·rad (believed)
Default 0
When to refine Last, and only for a group off a centre of symmetry (S is 0 at one).
Limits None.
Class atomic (FullProf's relaxation class; believed: displacements of the group's atoms)
Largest shift per cycle 0.005 Å·rad
In the core Phase.rigid

Symmetry-mode polarisation vector

mode_vector · \(\mathbf{V}_{mj}\) · fraction of the cell edge · read, not refined

The displacement of atom j in mode m, fixed by group theory (AMPLIMODES); normalised so that its squares over the distorted structure's primitive cell make 1 Ų in the reference (parent) metric, so amplitudes scale with that metric.

\(\sum_{j \in \text{primitive cell}} \mathbf{V}_{mj}^{T} G_0\, \mathbf{V}_{nj} = \delta_{mn}\ \text{Å}^2\)

Equation as printed in: nb5132.md L255. Paper: D. Orobengoa, C. Capillas, M. I. Aroyo & J. M. Perez-Mato (2009). AMPLIMODES: symmetry-mode analysis on the Bilbao Crystallographic Server. J. Appl. Cryst. 42, 820–833

FullProf V_MODES lines: mode, atom, irrep, Vx Vy Vz, coefficient (fp2k.inf, 29 August 2008)
GSAS-II the displacive-mode vectors of an ISODISTORT CIF (GSASIIstrIO.py L305)
Range fixed by the structure: |V| shrinks as the primitive cell holds more atoms
Default none: read (AMPLIMODES, a mode .pcr)
When to refine Never: fixed by symmetry.
In the core Phase.modes

Reflection intensity

reflection_intensity · \(I_h\) · counts · refinable

The integrated intensity of a reflection given directly, with no structure: extracted at each cycle by Le Bail's partition (profile matching, Jbt = 2), or refined by least squares with the cell and profile in a Pawley fit (P36), reflections that coincide for every cell the crystal system allows tied with equal |F|² (I_h in proportion to the multiplicity).

\(y_{ci} = \sum_h I_h\, \Omega(2\theta_i - 2\theta_h) + b_i\)

Equation as printed in: FullProf_Manual.pdf, p. 14 · FullProf_Manual.pdf, p. 15. Paper: G. S. Pawley (1981). Unit-cell refinement from powder diffraction scans. J. Appl. Cryst. 14, 357–361. doi:10.1107/S0021889881009618

FullProf the CODFILn.hkl file of a phase with Jbt = 2, Irf = 2 (p. 15); FullProf has no Pawley fit (p. 14 names the method only)
GSAS-II PWLref, a Pawley reflection's F\(^{2}\) refined with the cell and profile, the coincident ones equivalenced (GSASIIstrIO.py, GetPawleyConstr), a penalty on negative values (GSASIIstrMath.py, penaltyFxn, 'Pawley neg wt')
Range whatever the data give
Default none
When to refine Le Bail: each cycle, from the observed pattern. Pawley: refined with the cell and profile, the scale factor held (the list's intensity has none).
Limits \(\ge 0\) (a Pawley intensity held at zero where the data push it below; GSAS-II penalises negative ones instead).
Class profile (FullProf's relaxation class; believed: FullProf, which has no Pawley fit, names no class for it)
Largest shift per cycle none
In the core Phase.intensities

Calculation controls

TOF range end

tof_max · \(T_{\max}\) · µs · read, not refined

The pattern's last time of flight, the period of the Fourier background.

\(b_i = \sum_j B_j \cos\frac{j \pi T_i}{T_{\max}}\)

Equation as printed in: FullProf_Manual.pdf, p. 76. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf's Fourier background in TOF: C = T_max/π, where the manual (p. 47) writes C = T_max; arg_si_calc.prf's background met to its print, 0.03 (L341).

FullProf TOF-max, line 9 of a TOF pattern (p. 76)
GSAS-II the histogram's upper limit
Range 19380.8–247540.2 µs on the six TOF runs of L334 (arg_si, CeO2_PEARL, alum, lamn_pol, nac_osiris, gabriela's TOF pattern)
Default none: read
When to refine Never.
In the core Model.tof

Peak window

peak_window · \(W_{dt}\) · FWHM · read, not refined

The half-range over which a peak is calculated, in units of its FWHM; beyond it the profile is zero.

\(\Omega(x) = 0 \quad\text{for}\quad |x| > W_{dt}\, H\)

Equation as printed in: FullProf_Manual.pdf, p. 75. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

The default calculates each peak to ±Wdt·H and tapers it to zero by \(\pm\)1.25·Wdt·H, so that \(\chi^2\) is continuous as widths and positions change (L058; FullProf cuts it at the edge: Convention::window_edge). FullProf counts the window without X tan \(\theta\) for TCH and takes one more low point when X ≠ 0 (L035, L042): Convention::peak_window. No exact translation: a .pcr keeps FullProf's window on import (L050); switching it to the default moves \(\chi^2\) by up to 6.2% on the FullProf runs (YVO3, with the tapered edge, L058).

FullProf Wdt, line 8 (p. 75)
GSAS-II none: GSAS-II sets the range from the peak's own shape
Range 5–55.5 (median 8)
Default none: read
When to refine Never; 4 for Gaussian peaks, 20–30 for Lorentzian ones (p. 75).
In the core Model.wdt

Asymmetry limit

asymmetry_limit · \(2\theta_{\mathrm{asym}}\) · deg 2\(\theta\) · read, not refined

The angle below which the asymmetry corrections are applied.

\(A(z) \text{ and } \Omega_{\mathrm{FCJ}} \text{ for } 2\theta_h < 2\theta_{\mathrm{asym}}\)

Equation as printed in: FullProf_Manual.pdf, p. 75. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf AsyLim, line 8 (p. 75)
GSAS-II none
Range 30–180 (median 170)
Default none: read
When to refine Never.
In the core Model.asym_limit

Excluded regions

excluded_regions · \([2\theta_a, 2\theta_b]\) · deg 2\(\theta\) · read, not refined

Ranges of the pattern left out of the calculation and of the agreement factors.

\(y_{ci} = b_i \quad\text{for}\quad 2\theta_a \le 2\theta_i \le 2\theta_b\)

Equation as printed in: FullProf_Manual.pdf, p. 78. Paper: J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf)

FullProf also leaves out a point whose step reaches into a region (L033): Convention::excluded_points. On import with the data, each run of points FullProf leaves out becomes a region from its first to its last point, exactly (L050).

FullProf ALOW, AHIGH, line 11 (p. 78)
GSAS-II Excluded regions of the histogram's limits
Range as the data need
Default none
When to refine Never.
In the core Model.excluded

References

  • H. M. Rietveld (1969). A profile refinement method for nuclear and magnetic structures. J. Appl. Cryst. 2, 65–71. doi:10.1107/S0021889869006558. Checked: mindat reference record; IUCr dictionary, Rietveld method
  • H. M. Rietveld (1967). Line profiles of neutron powder-diffraction peaks for structure refinement. Acta Cryst. 22, 151–152. doi:10.1107/S0365110X67000234. Checked: Wikipedia, Hugo Rietveld; IUCr dictionary; cited by FullProf's manual, p. 5
  • G. Caglioti, A. Paoletti & F. P. Ricci (1958). Choice of collimators for a crystal spectrometer for neutron diffraction. Nucl. Instrum. 3, 223–228. doi:10.1016/0369-643X(58)90029-X. Checked: read in manuals/papers/Caglioti_Paoletti_Ricci_1958.pdf (L050): the Gaussian FWHM of eq. 11 (p. 225) is quadratic in a = tan \(\theta\) / tan \(\theta\)_M (eq. 5, p. 224), whence U tan\(^{2}\)\(\theta\) + V tan \(\theta\) + W; DOI from Crossref (manuals/papers/README.md)
  • P. Thompson, D. E. Cox & J. B. Hastings (1987). Rietveld refinement of Debye–Scherrer synchrotron X-ray data from Al2O3. J. Appl. Cryst. 20, 79–83. doi:10.1107/S0021889887087090. Checked: read in manuals/papers/Thompson_Cox_Hastings_1987.pdf (L050): the pseudo-Voigt (eq. 1), η (eq. 2) and H (eq. 3), p. 80, are the core's and FullProf's eqs. 3.16–3.17 coefficient for coefficient; F_G (eq. 4, p. 81), F_G = V tan \(\theta\) and F_L = X/cos \(\theta\) (eqs. 8a, 8b, p. 82). Pages and DOI from Crossref (L047)
  • L. W. Finger, D. E. Cox & A. P. Jephcoat (1994). A correction for powder diffraction peak asymmetry due to axial divergence. J. Appl. Cryst. 27, 892–900. doi:10.1107/S0021889894004218. Checked: read in manuals/papers/Finger_Cox_Jephcoat_1994.pdf (L050): sample height 2S and detector opening 2H at distance L (Fig. 1, p. 893); 2φ_min (eq. 4), 2φ_infl (eq. 5) and the Gauss–Legendre sum (eq. 9), p. 895, as the core's port of CrysFML's Prof_Val computes them with S/L, H/L as given
  • J.-F. Bérar & G. Baldinozzi (1993). Modeling of line-shape asymmetry in powder diffraction. J. Appl. Cryst. 26, 128–129. doi:10.1107/S0021889892009725. Checked: read in manuals/papers/Berar_Baldinozzi_1993.pdf (L050): g = g₀[1 + A(\(\theta\))F_a(dθ/w) + B(\(\theta\))F_b(dθ/w)] (eq. 14), F_a = 2z exp(−z\(^{2}\)) (eq. 12), F_b = (8z\(^{3}\) − 12z) exp(−z\(^{2}\)) (eq. 13), A(\(\theta\)) = A₀/tan \(\theta\) + A₁/tan 2\(\theta\) (eq. 15), p. 129; dθ > 0 on the low-angle side (eqs. 1–3, p. 128)
  • W. A. Dollase (1986). Correction of intensities for preferred orientation in powder diffractometry: application of the March model. J. Appl. Cryst. 19, 267–272. doi:10.1107/S0021889886089458. Checked: read in manuals/papers/Dollase_1986.pdf (L050): the sum of P over the m symmetry-equivalent planes (eq. 4) and the profile functions of Table 1 (nos. 1–6), p. 268; pages and DOI from Crossref (L047)
  • A. March (1932). Mathematische Theorie der Regelung nach der Korngestalt bei affiner Deformation. Z. Kristallogr. 81, 285–297. doi:10.1524/zkri.1932.81.1.285. Checked: read in manuals/papers/March_1932.pdf (L050): the pole density of an affine deformation is the cube of the deformation ellipsoid's radius, ρ_max/ρ_min = (a/c)³ (p. 291); its axial case is Dollase's Table 1, no. 6
  • J. Rodríguez-Carvajal (1993). Recent advances in magnetic structure determination by neutron powder diffraction. Physica B 192, 55–69. Checked: cristal.org citation record; cited by FullProf's manual, p. 14
  • R. J. Hill & C. J. Howard (1987). Quantitative phase analysis from neutron powder diffraction data using the Rietveld method. J. Appl. Cryst. 20, 467–474. Checked: cited by FullProf's manual, p. 32 (which prints pp. 467–476); not read: not in manuals/papers/
  • J. Rodríguez-Carvajal, notes on symmetry modes in FullProf (fp2k.inf, 29 August 2008 – 20 May 2010), reproduced in the tutorial 'AMPLIMODES and FullProf: symmetry modes crystallography' (manuals/fullprof/7-FullProf-Tutorial-SymmetryModes/FullProf-Tutorial-Symmetry-Modes.pdf). Checked: read (L090): Jbt = 6, V_MODES, A_MODES, the position r = r_HS + Σ Q·V·coeff, Max_Amplitude, the FST options of the A_MODES line, esd's without correlations (pp. 3–5 of the PDF's text)
  • J. Rodríguez-Carvajal, restraints and rigid bodies in FullProf (manuals/fullprof/docs/FullProf-Restraints-RigidBodies.pdf), after V. Rodríguez's STRMOD, 'General Rigid-Body-Constraints/TLS Subroutine' (FullProf's manual, pp. 32–36). Checked: read (L345): the internal coordinates of KIND 0–3, the Euler matrix R = R_z(φ) R_y(\(\theta\)) R_z(\(\chi\)) with r_C = R r_m + r_o (p. 8), the TLS matrices (pp. 8–9), P6's options and satellites (pp. 10–15); the Z-matrix's third atom and the torsion's sense found on FullProf's outputs (test rigid_bodies); TLS's β against FullProf's .ort files (L367, test tls)
  • B. Orayech, A. Faik, G. A. López, O. Fabelo & J. M. Igartua (2015). Mode-crystallography analysis of the crystal structures and the low- and high-temperature phase transitions in Na0.5K0.5NbO3. J. Appl. Cryst. 48. Checked: read in manuals/bcs/mode-crystallography-manual/articles/nb5132.md (L090): the normalisation (1 Å over a unit cell in the reference metric) and the global amplitude with its polarisation vector, lines 255–262; page numbers not in the copy
  • D. Orobengoa, C. Capillas, M. I. Aroyo & J. M. Perez-Mato (2009). AMPLIMODES: symmetry-mode analysis on the Bilbao Crystallographic Server. J. Appl. Cryst. 42, 820–833. Checked: cited by Orayech et al. (2015), reference list (nb5132.md, line 394); not read: not in the repository
  • J. Rodríguez-Carvajal (2001). An introduction to the program FullProf 2000. Laboratoire Léon Brillouin, CEA-CNRS (manuals/fullprof/FullProf_Manual.pdf). Checked: the copy in the repository
  • J. Rodríguez-Carvajal. Study of micro-structural effects by powder diffraction using the program FullProf. Laboratoire Léon Brillouin (manuals/fullprof/docs/Microstructural_effects.pdf). Checked: the copy in the repository
  • G. S. Pawley (1981). Unit-cell refinement from powder diffraction scans. J. Appl. Cryst. 14, 357–361. doi:10.1107/S0021889881009618. Checked: cited by FullProf's manual, p. 14 (Pawley's method named beside Le Bail's); not read: not in manuals/papers/
  • B. H. Toby & R. B. Von Dreele (2013). GSAS-II: the genesis of a modern open-source all purpose crystallography software package. J. Appl. Cryst. 46, 544–549. doi:10.1107/S0021889813003531. Checked: IUCr software directory; APS