Dear Gromacs experts,
I've been trying to use a tabulated potential for the
coulombic-interactions with all Gromacs versions from 4.0.7 to 4.5.3.
In combination with OPLS/AA force field and SPC/E water I used a
potential by Gezelter for a simple system consisting of a protein in
Water+Ions:
Fennell, Christopher J. ; Gezelter, J. D.: Is the Ewald summation still
necessary? Pairwise alternatives to the accepted standard for long–range
elec- trostatics. In: Journal of Chemical Physics 124 (2006)
When I run mdrun I specify sth. like this:
mdrun_mpi_s -table table_gezelter_s.xvg -tablep table_gezelter_s.xvg -v
-deffnm file.tpr
My problem is that the 14 Coulomb-energy is approximately half the value
of that compared to PME-switch.
The Coulomb-SR energy is approximately at the same value as PME and
everything else works alright.
So there's sth. wrong with the 1,4 energies. Since OPLS/AA uses a
scaling factor of 1/2 for the 1,4-interactions changing it will mess up
the whole simulation since the 1,4 LJ energies will get wrong. If I use
another table for the 1,4 interactions multiplied by a factor of 2
everything gets worse.
As a consequence this potential fails to reproduce densities etc.
So what am I missing? Is it the potential that's wrong?
Thanks alot for any ideas!
Christian
--
Christian Mücksch
Department of Physics
TU Kaiserslautern
Erwin Schrödinger Straße
67663 Kaiserslautern
Germany
Phone: +49 (0)631 205 4287
Fax: +49 (0)631 205 4965
Email: mueck...@rhrk.uni-kl.de
--
gmx-users mailing list gmx-users@gromacs.org
http://lists.gromacs.org/mailman/listinfo/gmx-users
Please search the archive at
http://www.gromacs.org/Support/Mailing_Lists/Search before posting!
Please don't post (un)subscribe requests to the list. Use the
www interface or send it to gmx-users-requ...@gromacs.org.
Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
