[gmx-users] T-coupling/freeze groups

[David van der Spoel]

On Wed, 17 Apr 2002, Rainer Boeckmann wrote:

>Hi,
>
>simulating a large water box at 1000bar with a numer of atoms (1000) freezed I
>get a continuous temperature increase of 4K during 10ps after switching off the
>temperature coupling. For the freezed atom group the non-bonded interactions are
>additionally excluded. Does anyone know about the source of this temperature
>increase?
Check a few things please:
1. Are you using a cut-off? Then you will get large temperature increase
   if you switch off t coupling (also without freezing atoms)
2. Have you defined center-of-mass motion removal group for the frozen 
   atoms? Otherwise they will still move.
3. Is you time step too long (particularly since you run at 1000 bar)?

-- 
Groeten, David.
________________________________________________________________________
Dr. David van der Spoel, 	Biomedical center, Dept. of Biochemistry
Husargatan 3, Box 576,  	75123 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://zorn.bmc.uu.se/~spoel
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