[gmx-users] Re: DMSO G53a6 FF in Gromacs
gmx3 at hotmail.com
Wed Mar 12 17:29:58 CET 2008
> Date: Wed, 12 Mar 2008 17:20:19 +0100
> From: andreas.frank at ch.tum.de
> To: gmx-users at gromacs.org
> Subject: Re: [gmx-users] Re: DMSO G53a6 FF in Gromacs
> Dear all,
> I think I found the reason for the deviation after "hunderds of small
> runs"...:-): I normally used Dispersion Correction for both the energy
> and pressure because in the manual the following is noted:
> "...The pressure correction in contrast is very large and can not be
> neglected. Although it is in principle possible to
> parameterize a force field such that the pressure is close to 1 bar even
> without correction, such a method makes
> the parameterization dependent on the cut-off and is therefore
> undesirable. Please note that it is not consistent to
> use the long range correction to the dispersion without using either a
> reaction field method or a proper long range
> electrostatics method such as Ewald summation or PPPM."
> Maybe I got it wrong (and I am still a little bit confused) but because
> I used the reaction-field approximation I turned on DispCorr for
> Pressure. However, it seems that the Gromos DMSO FF was established in a
> way that the correction is "included" in the parameter set which was /
> is not clear to me when reading the DMSO paper.
Reaction-field is for electrostatics and has nothing to do with dispersion correction,
which is for Van der Waals interactions.
Gromos force fields never use a dispersion correction.
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