Initial velocities in QMD


Just Got Here
Hi everybody,
I'm wondering if it is possible to give initial velocities from an input file for a qmd calculation,
instead of using the temperature
in the Boltzmann distribution.

Thank you in advance,
Fabio

Forum Regular
This is possible through the restart file (.qmdrst). The format of the restart file is:

4
0 0.000000
Coordinates
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
Velocities
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000
0.000 0.000 0.000

The first line gives the number of atoms, the second line gives the step number and kinetic energy, and then come the coordinates and velocities (both in atomic units). If you want to specify your own initial velocities just create a restart file in this format with the initial coordinates and velocities that you want to use and set the step number to zero (it actually will not matter what you put as the kinetic energy since it will be recalculated from the velocities but you do need to have a number there).

Best,
Sean


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