post processing for calculating the vibrational density of state


I searched the previous lammps users usually produce velocity vector and do post-processing with those velocity vectors using Matlab for calculation of phonon density of state.

I would like to calculate the vibrational density of state.I have dumped the velocity(vx,vy,vz)? Could you give me some information how to do the post-processing in details( I know Matlab)?

How can I calculate the VDOS in particular region of my simulation box?

I am grateful if you could reply me.

Thank you

All best

Liyi Bai

From the atomic velocities calculate the velocity autocorrelation function, then take the Fourier transform (with Matlab). This will give you the Phonon DOS, provided that your MD trajectories had reached equilibrium.

An alternative to the above is to use the User-Phonon package, which gives you the dynamical matrix directly.