Re: VDW energy: positive or negative?

From: Axel Kohlmeyer (akohlmey_at_gmail.com)
Date: Tue Mar 04 2014 - 17:28:08 CST

On Mar 4, 2014 6:22 PM, "PANAGIOTA KYRIAKOU" <kyria008_at_gmail.com> wrote:
>
> Hello,
>
> I was wondering if someone could give me a rigid and detailed explanation
of why the VDW energy is positive in many systems (while the total energy
is negative), such as a protein in a solvated box? I read at a previous
post that it is related to the water model (
http://www.ks.uiuc.edu/Research/namd/mailing_list/namd-l.2005-2006/3358.html
).
> Could someone provide some more details on this issue?

Trivial. Because Coulomb interactions in those cases are stronger than
dispersion, so you end up on the repulsive branch of the lennard -Jones
potential. For more information, please refer to relevant papers describing
force field paramerization. No need to write a review of them just for you
here...

Axel
>
> This is a general question and not specific to a simulation run , so this
is why I am not including any input/output files.
>
> Giota
>
>
>
> Panagiota Kyriakou
>
> Graduate Student
>
> Dept. of Chemical Engineering and Materials Science
>
> University of Minnesota
>
>
> email: kyria008_at_umn.edu

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