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[求助]
GSAS精修求助 已有2人参与
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最近在学用GSAS-2精修一个结构，遇到了个问题，想求助各位虫友 自己的数据是用布鲁克收集的（步长），用的是GSAS里默认的仪器文件（defaults for CuKa lab data） 第一步修scale factor和background（background用的chebyschev，No.coeff. = 12） 修完后Final residuals: wR = 28.014% chi**2 = 430062.9 GOF = 10.30 Nobs = 4063 Nvals = 13 log10 MaxLambda = -3.0 第二步修Sample displacement和unit cell 修完后Final residuals: wR = 24.878% chi**2 = 339179.8 GOF = 9.15 Nobs = 4063 Nvals = 16 log10 MaxLambda = -3.0 第三步修size和microstrain 修完后Final residuals: wR = 7.496% chi**2 = 30794.4 GOF = 2.76 Nobs = 4063 Nvals = 18 log10 MaxLambda = -3.0 当我进一步精修原子位置时，wR反而升高了，很疑惑 Final residuals: wR = 33.559% chi**2 = 617155.6 GOF = 12.35 Nobs = 4063 Nvals = 18 log10 MaxLambda = -3.0 这是精修原子位置之前的图  可是进行原子位置精修之后，拟合线（上图中深绿色的线）却看不到了，误差线几乎和原始数据一样大了  求助各位，这是什么原因导致，该如何改进？@lich666@jackdeng |
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9楼2018-08-28 15:34:47
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附上精修原子位置之前的报告，求各位指点 ******************************************************************************** General Structure Analysis System-II Crystal Structure Refinement by Robert B. Von Dreele & Brian H. Toby Argonne National Laboratory(C), 2010 This product includes software developed by the UChicago Argonne, LLC, as Operator of Argonne National Laboratory. Please cite: B.H. Toby & R.B. Von Dreele, J. Appl. Cryst. 46, 544-549 (2013) ******************************************************************************** Least squares controls: Refinement type: analytic Hessian Maximum number of cycles: 3 Regularize hydrogens (if any): False Initial shift factor: 1.000 Phases: Phase name: Co0.333 Li1 Mn0.333 ======================================================================================================================================= X-ray scattering factors: Symbol fa fb fc --------------------------------------------------------------------------------------------------- Ni+2 11.41660 7.40050 5.34420 0.97730 3.67660 0.24490 8.87300 22.16260 0.86140 Li+1 0.69680 0.78880 0.34140 0.15630 4.62370 1.95570 0.63160 10.09530 0.01670 Co+3 10.33800 7.88173 4.76795 0.72559 3.90969 0.23867 8.35583 18.34910 0.28667 O-2 3.76936 2.53342 1.91579 1.55094 15.07970 6.30430 40.34450 0.31291 0.22789 Mn+4 9.96253 7.97057 2.76067 0.05445 4.84850 0.28330 10.48520 27.57300 0.25188 Neutron scattering factors: Symbol isotope mass b resonant terms --------------------------------------------------------------------------------------------------- Ni+2 Nat. Abund. 58.700 1.030 Li+1 Nat. Abund. 6.941 -0.190 Co+3 Nat. Abund. 58.933 0.249 O-2 Nat. Abund. 15.999 0.581 Mn+4 Nat. Abund. 54.938 -0.375 Space Group: R -3 m The lattice is centrosymmetric R-centered trigonal The Laue symmetry is 3m1 The lattice point group is -3m Multiplicity of a general site is 36 The inversion center is located at 0,0,0 The equivalent positions are: (0,0,0; 1/3,2/3,2/3; 2/3,1/3,1/3)+ ( 1) X, Y, Z ( 2) -Y, X-Y, Z ( 3) Y-X, -X, Z ( 4) Y-X, Y, Z ( 5) -Y, -X, Z ( 6) X, X-Y, Z Atoms: name type refine? x y z frac site sym mult I/A Uiso U11 U22 U33 U12 U13 U23 --------------------------------------------------------------------------------------------------------------------------------------- Li1 Li+1 0.00000 0.00000 0.00000 0.975-3m(100) 3 I 0.01000 Co1 Co+3 0.00000 0.00000 0.50000 0.333-3m(100) 3 I 0.01000 Ni1 Ni+2 0.00000 0.00000 0.50000 0.309-3m(100) 3 I 0.01000 Mn1 Mn+4 0.00000 0.00000 0.50000 0.333-3m(100) 3 I 0.01000 O1 O-2 0.00000 0.00000 0.24110 1.000 3m(100) 6 I 0.01000 Li2 Li+1 0.00000 0.00000 0.50000 0.025-3m(100) 3 I 0.01000 Ni2 Ni+2 0.00000 0.00000 0.00000 0.025-3m(100) 3 I 0.01000 Unit cell: a = 2.85871 b = 2.85871 c = 14.22720 alpha = 90.000 beta = 90.000 gamma = 120.000 volume = 100.691 Refine? True Spherical harmonics texture: Order:0 Phase: Co0.333 Li1 Mn0.333 in histogram: PWDR Pristine.gsa Bank 1 ======================================================================================================================================= Phase fraction : 1.0000 Refine? False Extinction coeff: 0.0000 Refine? False March-Dollase PO: 1.0000 Refine? False Axis: 0 0 1 Size model : isotropic equatorial: 1.000 Refine? True LG mixing coeff.: 1.0000 Refine? False Mustrain model: isotropic equatorial: 1000.0 Refine? True LG mixing coeff.: 1.0000 Refine? False Hydrostatic/elastic strain: names : D11 D33 values: 0 0 refine: False False Histogram: PWDR Pristine.gsa Bank 1 histogram Id: 0 ======================================================================================================================================= Instrument type: Bragg-Brentano Histogram limits: 5.00 deg to 85.01 deg Sample Parameters: Goniometer omega = 0.00, chi = 0.00, phi = 0.00 name : Scale Shift Transparency SurfRoughA SurfRoughB value : 49.9640 -51.1872 0.0000 0.0000 0.0000 refine: True True False False False Instrument Parameters: name : Azimuth Bank I(L2)/I(L1) Lam1 Lam2 Polariz. SH/L U value : 0.000000 1.000000 0.500000 1.540500 1.544300 0.700000 0.002000 2.000000 refine: False False False False False name : V W X Y Zero value : -2.000000 5.000000 0.000000 0.000000 0.000000 refine: False False False False False Background function: chebyschev Refine? True Coefficients: 1121.560 -540.523 -660.275 2450.153 4420.846 -8734.928 -9989.495 9915.896 8358.299 -602.288 -1347.907 -3599.143 Refinement results: --------------------------------------------------------------------------------------------------------------------------------------- Number of function calls: 7 No. of observations: 4063 No. of parameters: 18 User rejected: 0 Sp. gp. extinct: 0 Refinement time = 2.292s, 0.573s/cycle, for 4 cycles wR = 7.50%, chi**2 = 30794.4, GOF = 2.76 ---------------------------------------------------------------------------------------------------------------------------------- Variables generated by constraints name : 0::A0 value : 0.1640 sig : 0.0000 Phases: Result for phase: Co0.333 Li1 Mn0.333 ======================================================================================================================================= Reciprocal metric tensor: names : A11 A22 A33 A12 A13 A23 values: 0.164031945 0.164031945 0.004933352 0.164031945 0.000000000 0.000000000 esds : 0.000006881 0.000000456 New unit cell: names : a b c alpha beta gamma Volume values: 2.851052 2.851052 14.237342 90.0000 90.0000 120.0000 100.224 esds : 0.000100 0.000100 0.000657 0.007 Atoms: name x y z frac Uiso U11 U22 U33 U12 U13 U23 --------------------------------------------------------------------------------------------------------------------------------------- Li1 Li+1: values: 0.00000 0.00000 0.00000 0.975 0.01000 sig : Co1 Co+3: values: 0.00000 0.00000 0.50000 0.333 0.01000 sig : Ni1 Ni+2: values: 0.00000 0.00000 0.50000 0.309 0.01000 sig : Mn1 Mn+4: values: 0.00000 0.00000 0.50000 0.333 0.01000 sig : O1 O-2: values: 0.00000 0.00000 0.24110 1.000 0.01000 sig : Li2 Li+1: values: 0.00000 0.00000 0.50000 0.025 0.01000 sig : Ni2 Ni+2: values: 0.00000 0.00000 0.00000 0.025 0.01000 sig : Phase: Co0.333 Li1 Mn0.333 in histogram: PWDR Pristine.gsa Bank 1 ======================================================================================================================================= Final refinement RF, RF^2 = 4.63%, 10.08% on 18 reflections Durbin-Watson statistic = 0.340 Bragg intensity sum = 9.44e+05 Size model: isotropic equatorial: 0.00100, sig: 0.1551 LG mix coeff.: 1.0000 Mustrain model: isotropic equatorial: 5402.9, sig: 97.1 LG mix coeff.: 1.0000 Histogram: PWDR Pristine.gsa Bank 1 histogram Id: 0 ======================================================================================================================================= PWDR histogram weight factor = 1.000 Final refinement wR = 7.50% on 4063 observations in this histogram Other residuals: R = 5.25%, R-bkg = 9.09%, wR-bkg = 7.50% wRmin = 2.72% Instrument type: Bragg-Brentano Resonant form factors: Element: Ni+2 Li+1 Co+3 Mn+4 O-2 f' : -3.004 0.001 -2.365 -0.530 0.049 f" : 0.509 0.000 3.614 2.805 0.032 Sample Parameters: names : Scale Shift Transparency SurfRoughA SurfRoughB values: 120.7487 -69.9699 0.0000 0.0000 0.0000 sig : 0.4811 1.6698 Background function: chebyschev value : 1030 -382.1 16.47 -106.6 1352 -748.9 -5410 4882 6871 -7212 -2079 2482 sig : 4.213 29.91 119.7 494.9 899 2702 2564 6325 3067 6604 1298 2528 Background sums: empirical 4.5e+06, Debye 0, peaks 0, Total 4.5e+06 |
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