[Pw_forum] Can QE outputs velocities in MD implemented by scf ?

[Paolo Giannozzi]

On Jan 3, 2013, at 2:51 , Tian Lan wrote:

> I am using scf to run the BO molecular dynamics (...).
> I did not see the output of of velocities.


ion_dynamics='md'? I don't think velocities are written anywhere,
but it should be simple to print them out. They are contained in
array "vel". They are however simply given by
(tau(t+dt)-tau(t-dt))(2dt), so if you have access to atomic positions
as a fuction of time, you can easily recalculate them, with no loss
of accuracy (if I remember correctly how the Verlet algorithm works)

P.
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Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222