[Ifeffit] S02

Scott Calvin scalvin at mail.slc.edu
Fri Oct 21 15:13:04 CDT 2005


Hi Juan,

Another suggestion in the mean time (until you can do a temperature series)
is to fit multiple coordination shells--there are some excellent papers by
Anatoly that do that with systems very much like yours. The reasoning is
that for very small samples, the coordination number of shells at higher
Reff will be suppressed MORE than the nearest neighbor coordination number,
with the ratio determined by the size and shape of the catalyst particles.
This helps some in separating coordination number effects from other
effects which have been mentioned (e.g. correlation with sigma2, sample
homogeneity, etc.). If the suppression in S02 is due to one of the latter
factors, I'd expect it to affect all coordination shells pretty much
equally, but if it's due to small crystallite size, it should be highly
influenced by including more shells in your fit. Combining this with, e.g.,
a temperature series might well provide you even more confidence that you
understand what's going on.

--Scott Calvin
Sarah Lawrence College
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