>Do a Feff calculation with each unique Co site as the absorbing atom,
>then use paths from each calculation, weighted by the fractional site
>occupancy.
>Cheers,
>--Matt

Thanks, Matt! Yes, that's exactly what I tried doing. It's a simple cubic lattice with

20 atoms per unit cell, 8 of one type (Co1) and 12 of the other (Co2). So I did two

FEFF runs in the same Artemis project, with Co1 and Co2 as the core atom, and

multiplied their respective amplitudes by 0.4 and 0.6. Then I noticed that if I calculate

a sum of all included paths I get a different FT spectrum than if the sums are calculated

separately for the two FEFF runs and averaged (with correct weighting) outside of

Artemis. Of course, it is a bit late here and I could be missing some obvious mistake.

On the other hand, I am trying for 1.6-5.5 angstrom fitting range, which involves 70+

paths for Co1 core and ~120 for Co2. Is it possible that Artemis does not like to deal

with too many paths and/or variables? I better go check the manual... :o)

Regards.

Vadim.