Raman Spectra Specific orientation

Dear all,

Briefly, im trying to calculate raman spectra of molecules that are fixed within a material. The qchem output gives only the activity and depolarization ratio, but i am interested, for example in the spectrum obtained when shining x-polarized light on the molecule and measuring the y-polarized raman scattering spectrum.

I did a lot of digging and what I found is that the raman polarizability tensor is typically calculated, by calculating the polarizability at displaced geometries, projected onto the normal modes, to give a raman polarizability tensor per normal mode. From this:

The mean polarizability and polarizability anisotropy can be calculated, and the final Raman activity, orientation average is calculated from these. What I would need is the raw Raman polarizability tensor per normal mode. - Would this be possible to get using Qchem?

So what you want are the polarizability derivatives, d(alpha_ij)/dx where x = 1,…,3N is a nuclear cartesian, which you could then transform into derivatives w.r.t. normal modes. Correct? The full set of polarizability derivatives are calculated whenever DORAMAN=TRUE (Raman vib intensity calculation), but they are not printed out. Would be easy to do if you have source code (developer) access.

Yes indeed! Would it be possible for me to get this?

If you have a valid Q-Chem license you can obtain source code access by signing a non-disclosure agreement. Please contact Q-Chem support.

When you are ready to do this, send me an email and I can show you the appropriate changes, seems straightforward based on a quick look at the code.