Script for calculating IR spectra

Hi developers,

I’ve written a script that calculates IR spectra based on a LAMMPS MD simulations, and I’d like to share it with the community. I’d be happy if you want to put it in LAMMPS’s included examples or on http://lammps.sandia.gov/user.html.

The code does a few things:

  1. It shows how to print out the net dipole moment of the system (implementing Axel’s method given in http://lammps.sandia.gov/threads/msg25750.html).
  2. It calculates the autocorrelation function of the net dipole moment.
  3. It computes the Fourier transform of the autocorrelation function to get the spectrum.

The files are attached, and can also be found at https://github.com/efremdan1/calc-ir-spectra-from-lammps. On the github page, I show the output files one obtains from running the code (since the LAMMPS simulation takes about 3.5 hours on a single core computer and the post-processing takes about 2.5 hours), but since it states on http://lammps.sandia.gov/user.html that the aggregate file size shouldn’t be too large, I’m guessing you wouldn’t want it.

calc-ir-spectra.py (5.51 KB)

data.infrared (57.9 KB)

in.infrared (3.33 KB)

README (2.94 KB)