[Pw_forum] Raman intensity with or without ASR

[Antoine JAY]

Hi,

I have calculated a lot of Raman Spectra with QE which give very accurated
results.

But when I try to calculate Raman intensities whith the eigenvectors
obtained after ASR (crystals) results aren't that accurate. The ASR do not
change my Raman frequencies, give 0 acoustic frequencies and change a bit
eigenvectors as expected.

Question: Why do I have to take eigenvectors which are calculated BEFORE
the ASR in the calcul of the intensity ?
(Equ.2 in Lazzeri, Mauri, PRL 90036401-1(2003))

Thanks a lot

Antoine JAY
Doctorant (PhD student)
Laboratoire des Solides Irradiés