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Re: [sdpd] V4+
While there are ways of modeling x-ray scattering from V4+ is it a good
thing to do?
I suspect that modeling the scattering from V(IV) in a compound using a gas
phase V4+ scattering factor is not a good approximation to reality for most
solids. Does anybody want to comment further on this?
Angus
At 02:28 PM 12/13/2004 +0100, Armel Le Bail wrote:
> >Where can I find Scattering coefficients for V+4and how to use those data
> >for the rietveld analysis? And what shall I do if the valance of vanadium
> >is between +4 and +5?
>
>This seems to be possible :
>
>In FullProf, use NSCAT < 0 (linear interpolation).
>
>Pages 489 and 490 of the International Tables for Crystallography,
>calculate the atomic scattering factor for V4+ as being the
>average of V3+ and V5+. f(0) = 19.000, etc. This would
>certainly be a fair approximation.
>
>Enter the appropriate values at lines 8-1 and 8-2 (see the manual) :
>
>Line 8-1 : NAM, DFP, DFPP,ITYM
>Line 8-2 :
> or a set of lines of the form : sin(Theta)/l - f
> The set is terminated by a line with -100 in first position.
>
>Note(2): If you
> want a linear interpolation NSCAT must be negative and the
> list is given as: 1000.0*2sin(Theta)/L- f
>
>Hum, not clear what to use here, sin(Theta)/lambda
>or 1000.0*2sin(Theta)/lambda ???
>
>Best wishes,
>
>Armel
>
>PS - See the example file : c60a.pcr :
>COMM Single crystal data of C60 (X-ray,
>MoKa)
>! Current global Chi2 (Bragg contrib.) = 97.01
>! Files => DAT-file: c60, PCR-file: c60a
>!Job Npr Nph Nba Nex Nsc Nor Dum Iwg Ilo Ias Res Ste Nre Cry Uni Cor Opt Aut
> 0 0 1 0 0 -1 0 0 0 0 0 0 0 0 1 0 0 0 1
>!
>!Ipr Ppl Ioc Mat Pcr Ls1 Ls2 Ls3 NLI Prf Ins Rpa Sym Hkl Fou Sho Ana
> 0 0 1 1 1 0 0 0 0 1 0 0 0 0 0 0 0
>!
>!NCY Eps R_at R_an R_pr R_gl Thmin Step Thmax PSD
> Sent0
> 8 0.10 1.00 1.00 1.00 1.00 10.0000 0.100000 89.9000
>0.000 0.000
>!
>! Additional scattering factors for Pattern# 1
>c60 0.00000 0.00000 0
> 0.000 1.00000
> 22.599 0.95840
> 45.198 0.83990
> 67.797 0.66190
> 90.396 0.45010
> 112.994 0.23400
> 135.593 0.04170
> 158.192 -0.10450
> 180.791 -0.19150
> 203.390 -0.21710
> 225.989 -0.18930
> 248.588 -0.12390
> 271.186 -0.04140
> 293.785 0.03790
> 316.384 0.09720
> 338.983 0.12610
> 361.582 0.12220
> 384.181 0.09030
> 406.780 0.04080
> 429.379 -0.01300
> 451.977 -0.05840
> 474.576 -0.08570
> 497.175 -0.09030
> 519.774 -0.07310
> 542.373 -0.04010
> 564.972 -0.00010
> 587.571 0.03670
> 610.169 0.06210
> 632.768 0.07090
> 655.367 0.06210
> 677.966 0.03910
> 700.565 0.00820
> 723.164 -0.02280
> 745.763 -0.04640
> 768.362 -0.05750
> 790.961 -0.05410
> 813.559 -0.03790
> 836.158 -0.01350
> 858.757 0.01290
> 881.356 0.03480
> 903.955 0.04730
> 926.554 0.04770
> 949.153 0.03660
> 971.751 0.01720
> 994.350 -0.00550
>1016.949 -0.02590
>1039.548 -0.03910
>1062.147 -0.04230
>1084.746 -0.03510
>1107.345 -0.01970
>1129.943 -0.00010
>1152.542 0.01870
>1175.141 0.03220
>1197.740 0.03750
>1220.339 0.03340
>1242.938 0.02140
>1265.537 0.00460
> -100.0
>!
> 2 !Number of refined parameters
>!-------------------------------------------------------------------------------
>! Data for PHASE number: 1 ==> Current R_Bragg for Pattern# 1: 20.47
>!-------------------------------------------------------------------------------
> C60
>
>!
>!Nat Dis Ang Pr1 Pr2 Pr3 Jbt Irf Isy Str Furth ATZ Nvk Npr More
> 1 0 0 0.0 0.0 1.0 0 4 0 0 0 48.040 0 0 0
>!
>F m 3 m <--Space group symbol
>!Atom Typ X Y Z Biso Occ In Fin N_t Spc
>/Codes
>C c60 0.00000 0.00000 0.00000 7.18223 1.00000 0 0 0 0
> 0.00 0.00 0.00 21.00 0.00
>! Scale Factors
>! Sc1 Sc2 Sc3 Sc4 Sc5 Sc6
> 33.97 0.000 0.000 0.000 0.000 0.000
> 11.00 0.00 0.00 0.00 0.00 0.00
>! Extinction Parameters
>!
>Ext1 Ext2 Ext3 Ext4 Ext5 Ext6 Ext7
>Ext-Model
> 0.000 0.000 0.000 0.000 0.000 0.000 0.000
> 0
> 0.00 0.00 0.00 0.00 0.00 0.00
> 0.00
>! a b c alpha beta gamma
> 14.152000 14.152000 14.152000 90.000000 90.000000 90.000000
> 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000
>! x-Lambda/2 + Not yet used parameters
> 0.00000 0.00000 0.00000 0.00000 0.00000
> 0.00 0.00 0.00 0.00 0.00
>
>
>
>
>
>
>Yahoo! Groups Links
>
>
>
>
Dr. Angus P. Wilkinson School of Chemistry and
Biochemistry
Prof. Chemistry and Biochemistry Georgia Institute
of Technology
Prof. Materials Science and Engineering 770 State St.
Atlanta, GA 30332-0400
Tel: 404 894 4036
Fax: 404 894 7452
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