Re:

From: Ajasja Ljubetič (ajasja.ljubetic_at_gmail.com)
Date: Wed Jan 27 2016 - 03:39:04 CST

HI!

First of all some attention to punctuation and spaces would probably show
that you have put some effort into this e-mail.

The problem you are getting is very common; if you search the mailing list
archives you will get many answers.
Most likely there are some vdw overlaps that remain even after
minimization.

You can try a combination of the following:

   - Do a short run (~100 steps) of MD, followed by minimization, followed
   by short MD, followed by more minimization.
   - Do heating with the langevin thermostat and a very high viscosity (for
   example *langevinDamping *20).
   - Heat the system slowly (link
   <http://www.ks.uiuc.edu/Research/namd/mailing_list/namd-l.2009-2010/3066.html>
   ).
   - Reduce the timestep.

Best,

Ajasja

On 27 January 2016 at 06:06, Srijita Paul <srijitap91_at_gmail.com> wrote:

> hii,
>
> i am facing a problem while heating my system....i have done
> minimization successfully.then during heating its giving the following
> error after certain time..
> REASSIGNING VELOCITIES AT STEP 3480 TO 300 KELVIN.
> ERROR: Atom 1122 velocity is -4022.55 -3291.44 -1303.34 (limit is 5000,
> atom 39 of 1139 on patch 19 pe 0)
> ERROR: Atoms moving too fast; simulation has become unstable (1 atoms on
> patch 19 pe 0).
> ERROR: Atom 1120 velocity is 3989.65 3709.84 1498.93 (limit is 5000, atom
> 1143 of 1156 on patch 20 pe 0)
> ERROR: Atoms moving too fast; simulation has become unstable (1 atoms on
> patch 20 pe 0).
> ERROR: Exiting prematurely; see error messages above.
> ====================================================
> plz tell me how can i solve the problem.
>
>
>

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