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<DIV>Hi,</DIV>
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<DIV> This is Dr. Nithya Ravindran
from India. I am using GSAS II to extract structural information of double
perovskites and I have a couple of doubts to be clarified. They are listed
below:</DIV>
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<DIV>1. After a few iterations of refinement, a stable wR on 1399 observations
15.572% is obtained. Not able to refine further to reduce this value. Visual
inspection of the plot of experimental and computed powder diffraction profile
agrees well. Can this value be considered acceptable to rely on structural
parameters? We get Chi2 value very high (as high as 3213.91) and GOF 1.53;
and RF AND RF2 4.958% AND 9.369% respectively on 12 reflections. If not,
what should be the minimum value of wR for a good fit?<BR></DIV><FONT
face="Times New Roman"></FONT></DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000">2. in two
of the ruthenium and cobalt based double perovskites, Ru and Co exist in +5 and
+4 oxidation states respectively. Unable to select these ions as they are not
included in the program. Please clarify.</DIV>
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style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000"> </DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000">Thank
you,</DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000">With warm
regards,</DIV>
<DIV
style="FONT-SIZE: 12pt; FONT-FAMILY: 'Calibri'; COLOR: #000000">Nithya</DIV></DIV></DIV></DIV></DIV></BODY></HTML>