Broadening of Raman Spectra at 0K and at Finite Temperature

Running Abinit Link to other codes
1

Hi,

I was calculating for my material using the 2n+1 theorem, following the tutorial available at “Electronic non-linear susceptibility, non-resonant Raman tensor, electro-optic effect” Abinit web-page. Specifically saying, I was following tnlo_1.abi to tnlo_5.abi in Version 10.0.5 of ABINIT. Now, I have a few questions -

  1. At the ground state, there’re three phonon processes involved and even in finite temperature both of the three phonon and four phonon processes involved. I was looking for suggestion how can I obtain the phonon lifetime for the broadening of raman spectra from three phonon and four phonon processes?

  2. In case, if ABINIT had not implemented the 3-ph and 4-ph scattering processes, is there any other possible way to implement the broadening in Raman Spectra? I personally wouldn’t prefer to use a broadening by hand.

  3. I would also like to mention that, the python script available in the website for Raman Spectra at finite temperature it doesn’t consider Phonon Linewidth, please correct me if I’m wrong. Since, the broadening of Raman spectrum is associated with the 3-ph, 4-ph scattering processes and Phonon lifetime does this python script serve the purpose in this sense?

    Some tutorial files, and some article suggestions would have been much appreciated.

Thank you