Thank you all for kind replies. Following the advices, I ran FullProf putting ATZ=0 for both phases and I got the consistent weight fractions with my calculation using Wp=S_p(ZMV)_p/ΣS_i(ZMV)_i. Actually I found a description about ATZ=0 in fp2k.inf after getting replies. I am sorry for forgetting to do this before ask.
I still can not get the idea of ATZ even after Carlos’s explanation "Atz is the mass of the unit cell in atomic units." What does “f”’ in the manual actually mean? and why is “f" squared in the definition of ATZ? I don’t understand what "their true value” is. > Carlos I always use Ns/Ng for occupancies because I was taught to do so. I thought everyone uses normalized occupancies but it seems I was wrong judging from your advice. > Patrick Thanks for the caution. That may relate to my case because one of the two phases contains substituted atoms. I found a description below in July 4th 2011 update of fp2k.inf. > - In the new version of FullProf the calculation of ATZ takes into account > the first and second > atom of the list. In a compound with all sites partially occupied, it is > supposed that the two > first atoms are in the same site and occupy fully the site. In this case > the value of ATZ is > correctly calculated. For my case, there are nine sites and two of those are occupied by two kinds of atoms (Nat=11). And I want to refine their occupancies to know the site preference. The two sites are placed in the head of the atom list like below. !Atom … Occ A1 … 0.22000 B1 … 0.03000 A2 … 0.22000 B2 … 0.03000 C … D … Occupancies for site 1 and site 2 are set to maintain the normalized occupancy 0.25 using codewords. I think this does not violate your caution and the description in fp2k.inf. Maybe I should not ask why (only?) the first atom needs to be fully occupied… //================//================// Kotaro SAITO High Energy Accelerator Research Organization Institute of Materials Structure Science 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan //================//================// > > > From: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] On Behalf > Of Kotaro SAITO > Sent: den 24 februari 2015 11:53 > To: Rietveld_l@ill.fr > Subject: Quantitative phase analysis on FullProf > > Dear Rietvelders, > > Does anyone know how FullProf calculates weight fractions “Fract(%)” in a > .sum file? or Is there any known bugs for calculating ATZ? > > According to the manual, it seems that ATZ is used for calculating the > values... but no further information is written in the manual. > I am also wondering, in my case, why different phases have the exact same > value for ATZ. It should be different for different materials from the > definition in the manual. > Here are the related descriptions in my .out file. > Phase 1 > => The given value of ATZ is 688.48 the program has > calculated: 4345.96 > Phase 2 > => The given value of ATZ is 688.48 the program has > calculated: 576.91 > I confirmed that 4345.96 and 576.91 seem to be Z*Mw > > I calculated the weight fractions using the values in the sum file and a > equation Wp=S_p(ZMV)_p/ΣS_i(ZMV)_i (R. J. Hill and C. J. Howard, J Appl. > Cryst., 20, 467-474), and ended up in getting quite different fractions from > those in the .sum file. I got 97.3% and 2.7% with my calculation and the > values in the .sum file are like this. > Phase 1 > => Bragg R-factor: 2.74 Vol: 941.374( 0.009) Fract(%): > 82.46( 0.85) > => Rf-factor= 1.81 ATZ: 688.475 Brindley: > 1.0000 > Phase 2 > => Bragg R-factor: 7.65 Vol: 137.093( 0.079) Fract(%): > 17.54( 0.97) > => Rf-factor= 5.35 ATZ: 688.475 Brindley: > 1.0000 > > > When I ran an example pcr for quantitative phase analysis in Examples > (si3n4r.pcr), I got ATZ and weight fractions below > Si3N4 alpha > => The given value of ATZ is 560.00 the program has calculated: > 561.14 > Si3N4 beta > => The given value of ATZ is 280.00 the program has calculated: > 280.57 > > => Phase: 1 Si3 N4 alpha > => Bragg R-factor: 0.969 Vol: 292.623( 0.016) Fract(%): 92.88( > 0.44) > => Rf-factor= 0.600 ATZ: 560.000 Brindley: 1.0000 > > => Phase: 2 Si3 N4 beta > => Bragg R-factor: 2.26 Vol: 145.711( 0.027) Fract(%): 7.12( > 0.09) > => Rf-factor= 1.09 ATZ: 280.000 Brindley: 1.0000 > > and the these fractions are consistent with those derived from the equation > Wp=S_p(ZMV)_p/ΣS_i(ZMV)_i. > > I would like to know which weight fractions I should trust for my case… > > Best regards, > > Kotaro > > //================//================// > Kotaro SAITO > High Energy Accelerator Research Organization > Institute of Materials Structure Science > 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan > //================//================// > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
