[gmx-users] T-coupling/freeze groups

Rainer Boeckmann rboeckm at gwdg.de
Wed Apr 17 13:49:37 CEST 2002

> So then the question is: should the enrgy be conserved if one freezes
> atoms? Some considerations:
> - Physically, freezing is similar to giving the particles infinite mass

> - Is the force the derivative of the energy if we freeze particle?

> - Is the kinetic energy correct? We have zero velocities but infinite
>   masses

The frozen particles (zero charge) are kept frozen when switching off the
temperature coupling. I'd like to see them as a sort of wall. Therefore I used
initially separate T-coupling groups, one for the water at 300K, one for the
frozen atoms at 0K. I do not see a physical reason for a continuous temperature
increase after equilibration (started from different equilibration points) with
separate T-couplings. A solid wall shouldn't effect kinetic energy.

> - Do you have separate T-coupling group for the non-frozen atoms?


Rainer Böckmann
Theoretical Molecular Biophysics Group
Max-Planck-Institute for Biophysical Chemistry
Am Faßberg 11
D-37077 Göttingen

Tel.: +49(551)201-1141, Fax.: +49(551)201-1089
email: rboeckm at gwdg.de

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