Hi everyone,

There are 4 terms in the output of VACF computing style. The 4th term is the total VACF. I don’t understand why it directly sums the other 3 terms up.

If I want to calculate total vibration spectrum or total phonon density of state. Can I just simply apply FFT to the 4th term of the output?

Thank you very much.

Sincerely,

Yuan

Not sure what you are asking. The doc page says what

the 4 outputs are, and you can look at the source

code in compute_vacf.cpp if you are unsure.

They are the VACF at a point in time, relative to

a time origin.

How you use those outputs is up to you.

The compute vacf doc page gives one example,

e.g. to time integrate them for a diffusion coeff.

Steve