Dear all, I am fitting a Pt9Co1 foil sample.

`I assume the sample to be basically fcc platinum with every 10th atom`

`randomly replaced by cobalt.`

Here are the assumptions I make: 1. every atom has 12 nearest neighbors

`2. every Pt atom has (on average) 10.7 Pt nearest neighbors and 1.3 Co`

`nearest neighbors`

`3. every Co atom has (on average) 11.7 Pt nearest neighbors and 0.3 Co`

`nearest neighbors`

`I have been told that assumptions 2 and 3 are not precise. Here is what`

`I'm confused about:`

`In order to determine the number of Pt or Co nearest neighbors I looked`

`at an ensemble of 13 atoms:`

1 absorber and 12 scatterers/nearest neighbors.

`I assume that the Pt/Co ratio in this ensemble is 9/1 and therefor,`

`statistically, 1.3 out of those 13 atoms should be Co. That means that`

`if Co is the central atom only 0.3 Co atoms are remaining for the 12`

`nearest neighbors. On the other hand, if Pt is the central atom, (all)`

`1.3 Co atoms are remaining for the 12 nearest neighbors.`

`I have been told that the ratio of Pt/Co should be 9/1 in the 12 nearest`

`neighbors, not in the 12 atoms including the central atom (quote:`

`"because we have a bulk sample").`

But I do not understand why. Can someone please explain the correct answer to me? With kind regards, Felix _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit