[Pw_forum] Can I obtain IR spectrum from CPMD trajectory in Quantum Espresso?

[Mostafa Youssef]

Dear Yin,

You already got great suggestions. I would like to add one more option to calculate IR from ab initio MD. You could do scf calculation on each configuration obtained via MD to calculate Maximally Localized Wannier Functions (MLWF). From MLWF you could calculate the dipole moment of the simulation cell or even for single molecules inside the cell at each time step. It is straightforward to obtain IR  once you have the dipole moment at each time step.

An example for this option can be found here:

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.98.247401

Note that the authors of this paper implemented Wannier on the fly which I think is not available in Q.E. But the computational cost to re-track the trajectory and calculate MLWF should not be too expensive if one already affords the MD run.


Mostafa Youssef
MIT


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