Leandro : here is an example of calcite I used. You can use min and max to confine the parameters.
One way to know whether it is right is to mix a known fraction of a compound, e.g. ZnO with a ratio of original sample/ZnO=100/15. At the end of the refinement, you have N components with N corrected(with volume and density) scalefactor, S(i), Weight(i)=S(i)/S(ZnO)*15 the sum of all weight(i) should be close to 100 if the whole thing is crystalline. str phase_name calcite scale sc_calcite 0.0001813894308 space_group R-3c r_bragg 5.769971925 Crystallite_Size(cs_calcite, 100 min =100; max =1000;) Trigonal(a_calcite 4.995096119 min =4.95; max =5.2;,c_calcite 17.08621648 min =16.9; max =17.1;) site Ca num_posns 6 x 0 y 0 z 0 occ Ca+2 1 beq 0.95 site C num_posns 6 x 0 y 0 z =1/4; : 0.25 occ C 1 beq 0.9 site O1 num_posns 18 x 0.257 y 0 z =1/4; : 0.25 occ O-2 1 beq 0.94 PO_Spherical_Harmonics(sh_calcite, 2 ) Cheers J Hi, guys, I´m having some trouble using the Bruker software TOPAS R, right now I´m quantifying a sinthetic sample with 50% of calcite and 50% of dolomite. Check the following questions an help me if you can. 1) I´m using the CIF files from ICSD, but when I put it in the software it gives me a temperature factor (beq.) of 1. Is there anyway I can check some good temperature factors?! When i put then to refine, sometimes they become negative, but the calculated - observed pattern is just good. 2) I´m using Fundamental Paramaters and for these I must have acknowledge of my instrument, well I have, minus sample lenght... and stuff like that... is there anyway I can determine these values with accuacy and use them with sure?! 3) In TOPAS how do I know if the refinement is good?! Because each time I refine the 50%/50% mixture I have different results and I don´t know wich one gives me a result that I can trust. Thank ou in advance, Leandro Bravo Ferreira da Costa Student, UFRJ - Universidade Federal do Rio de Janeiro - BR CETEM - RJ _________________________________________________________________ Inscreva-se no novo Windows Live Mail beta e seja um dos primeiros a testar as novidades-grátis. Saiba mais: http://www.ideas.live.com/programpage.aspx?versionId=5d21c51a-b161-4314-9b0e-4911fb2b2e6d
