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Re: [abinit-forum] Molecular Dynamics : particles going out of the box

From: "Anglade Pierre-Matthieu" <anglade@gmail.com>
To: forum@abinit.org
Subject: Re: [abinit-forum] Molecular Dynamics : particles going out of the box
Date: Thu, 2 Mar 2006 15:56:12 +0100
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Regarding the discussion of the time step to be chosen for hydrogen:

There is a simple rule of thumb for choosing MD time-step:
If you take "r" as a typical length in you cell (e.g. average 1nn distance),
"v" as a typical speed (e.g. average quadratic speed at equilibrium=
sqrt(3*k_b*T/m))
then your time step in second should be proportionnal to r/v.
Back to the late sixties, Verlet (phys rev 159 p98) was using a
proportionality factor of about 80 which should be considered as a
minimum. Nowadays people often use a factor of about 1500 in classical
MD (yet this is too big for ab initio MD).

I think a factor of a 100-200 should be OK for most situations.
regards
--
Pierre-Matthieu Anglade

Molecular Dynamics : particles going out of the box, vinayak, 03/02/2006
- Re: [abinit-forum] Molecular Dynamics : particles going out of the box, Per Andersson, 03/02/2006
  - Re: [abinit-forum] Molecular Dynamics : particles going out of the box, Nuno Galamba, 03/02/2006
    - Re: [abinit-forum] Molecular Dynamics : particles going out of the box, Anglade Pierre-Matthieu, 03/02/2006