[gmx-users] Temperature dependence of virial of an initial configuration

[Justin Lemkul]

On 3/17/16 11:50 AM, rakesh sharan wrote:
> Dear all,
>
> I have a question regarding computation of different components of virial of
> my starting initial configuration using Gromacs. When I am running job by
> setting nstep  = 0 (system is bulk spce water) to get potential energy and

Note that doing a run with zero steps is not a true single point evaluation.

http://www.gromacs.org/Documentation/How-tos/Single-Point_Energy

> components of virial of my starting configuration, I am observing that output
> components of virial are strongly temperature dependent, even though
> potential energy is fixed. This is very surprising to me, as one would expect
> that both energy and virial of a starting configuration should be independent
> of temperature. I would highly appreciate any thought over this temperature
> dependent virial of my initial configuration. I would also appreciate very
> much if you could suggest any robust way to get the contribution of virial to
> the total pressure of a given configuration.
>

Manual section A.1 describes the virial computation in detail.

-Justin

--
==================================================

Justin A. Lemkul, Ph.D.
Ruth L. Kirschstein NRSA Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 629
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalemkul at outerbanks.umaryland.edu | (410) 706-7441
http://mackerell.umaryland.edu/~jalemkul

==================================================