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!