Subject: Temperature problem with CHARMm restart

From: Ari Lahti IFK <[email-masked]>
Date: Thu, 10 Oct 1996 12:29:56 +0300 (EET DST)

Dear CCLers, 

I'm trying to run a MD simulation on a small bio-organic molecule using
CHARMm, version 23.1. I have a problem in keeping constant the 
temperature after a restart of the run. 

The temperature I want to use is 310 K, and my heating and equilibration 
phases have durations of 500 and 10 000 cycles (1 fs/cycle), respectively. 
At the end of the equilibration I have a temperature of 312 degrees. After 
that, everything works fine during the actual simulation run, unless I 
instead of a continuous run stop and restart the run again after the 
equilibration. The restarted run starts at 312 degrees but immediately 
thereafter the temperature goes down to 292 degrees. The temperature keeps 
at this low level all the way thereafter. 

I don't see what makes the temperature go down in the restarted run since
I'm using the same parameters in both running methods. The right starting
temperature at the beginning of the restarted run should guarantee that I'm
using the right .RST file. Can anybody explain to me what the reason for 
this kind of behaviour might be?

	regards
	--ari 

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* Ari Lahti, M.D., M.Sc.                          tel.: +358-2-2654951      *
* Dept. of Phys. Chem.                            fax:  +358-2-2654706      *
* Abo Akademi University                          e-mail: [email-masked]   *
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