Re: AMBER: vlimit exceeded in thermalization

From: David A. Case <>
Date: Tue, 29 Mar 2005 09:22:20 -0800

On Mon, Mar 28, 2005, Holly Freedman wrote:
> I am running a simulation of acetic acid in water, and I am starting
> with a thermalization run, where the temperature is slowly raised from 1
> to 298K. However the system seems to be reaching unreasonably high
> temperatures and exploding, i.e. vlimit is exceeded.

Have you minimized the structure first? How quickly is the temperature
rising? It is sometimes helpful to start with a target temperature of
50 to 100 K, and later heat to 300. But this should not be required for
the problem you describe.

So: be sure to minimize if you have not already done so. There should be
no need for a belly flag with a small solute in water (although this doesn't
appear to be a part of the problem, but you could check.) You might
double-check your force field generation strategy, and/or post a bit of the
output file (including the energy breakdowns).

....good luck...dac

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Received on Tue Mar 29 2005 - 18:53:00 PST
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