[Ifeffit] Question: About using polarization and ellipticity cards in FEFF

xu dongbin binbinmirror at gmail.com
Sun May 13 03:06:39 CDT 2012


Hi, 

I would like to ask a question which has confused me for a few days.

In my current case, I'm dealing with samples with c texture in the film normal. The sample was measured with linear polarized x-ray in both directions with the surface of sample parallel/perpendicular to the electrical field  of x-ray. During measurement, the sample was always rotated around the film normal. Therefore, I think the parallel direction data can be treated with random orientated grains in the film plane.

In order to describe this, I need use POLARIZATION and ELLIPTICITY cards in FEFF calculation. However, I'm not sure which case below is the correct one I should include in FEFF calculation for my case:

a. POLARIZATION  1 1 0 
    ELLIPTICITY 1 0 0 1

b. ELLIPTICITY 1 0 0 1

I think these two cases should give the same calculation results, however, when I sum the paths in these two cases respectively using the same parameters(S02, E0, delR, sigma^2). The results give substantial difference. Can anyone help me to figure out this?

Thanks&Regards!





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