Raman spectra of mixed oxides

GULP
1

Hi Dr. Gale,

I’ve been using GULP (v6.1) to simulate the Raman spectra of some mixed oxides. The agreement with experimental spectra has so far been reasonable. However, I was reading the “online guide to commands” for v6.0 and saw this under the “intensity” keyword:

Raman intensities are also now output. However, it should be noted that they are approximate and only
valid for systems with a single type of bond in (such as a silicate).

Could you point me to a paper that explains why the intensities are valid only for systems with a single type of bond? I could not find any mention of this in the GULP manual.

Thank you very much for your time,

Connor

2

Hi Connor,

The problem with Raman is that it depends on terms beyond dipole polarisability and most force fields don’t have this more sophisticated polarisation. The theory behind the approximate approach taken in GULP can be found in the papers of Kleinman and Spitzer, see for example:

Best regards,

Julian