[Ifeffit] FEFF calculation for two inequivalent absorbing sites

Robert Gordon ragordon at alumni.sfu.ca
Thu Apr 9 13:18:03 CDT 2015

Hi Eugenio,

Quick question: Did you change the tags for the Co atoms so that they are
If I do that, I get 4 and 6 coordinate results. you can import the cif file
twice, run atoms on both
sites (with tags different) and get the two feff inputs for running.


On Thu, Apr 9, 2015 at 5:01 AM, Eugenio Paris <eugenio.paris at gmail.com>

> Hello everybody,
> I'm trying to make Co K-edge EXAFS fitting for the Co3O4 compound (*.cif
> file is attached). The nearest neighbour of Co is oxigen at about 1.93
> Angstrom distance.
> Cobalt sits in two inequivalent sites in the unit cell. When I perform the
> FEFF calculation in Artemis for either one or the other site i get the same
> path with Reff = 1.93 and degeneracy = 4.
> So i wonder what is the correct way to take account of the presence of
> both sites. At the beginning i was thinking to put 2*amp as S0^2 parameter
> to take account for twice the coordination number.
> Then i tried to use the "Aggregate" option in Artemis. When I use this
> option i get exactly the same result, i.e. a SS path with Reff = 1.92 and
> degeneracy = 4... I was expecting to get twice the degeneracy.. (the margin
> and beta parameters are set to default)
> My question is:
> Why do i get the same path list when I do use the "Aggregate" pathfinder
> and when I don't? What is wrong in my interpretation?
> Thank you in advance!
> Sincerely,
> Eugenio
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