[gmx-users] Water models and force fields

Lieven Buts lieven at ultr.vub.ac.be
Tue Jul 9 09:38:25 CEST 2002

David wrote:
> This is a difficult topic, only testing can give you the answer. We have
> done some tests for peptides in different water models (J. Biomol. NMR
> 8, (1996) 229-238) and for pure water in different models (JCP 108
> (1998) 10220-10230). There are some other published comparisons too In
> general TIP3P should be avoided, TIP4P and SPC are decent, whereas SPC/E
> and TIP5P are only suitable for highly polar systems such pure water or
> maybe salt solutions.

Just to make sure: what would need to be done to use TIP4P instead of
I presume you have to run

   genbox -cp out.gro  -cs tip4p.gro   -o solv.gro   -p whatever.top

although this gives the following strange warning:

WARNING: masses will be determined based on residue and atom names,
         this can deviate from the real mass of the atom type
Opening library file
Mass of atom SOL MW4 set to 12.011

Then the section 

; Include water topology
#ifdef FLEX_SPC
#include "flexspc.itp"
#include "spc.itp"

would have to be changed, but I do not know exactly how.

Lieven Buts
Vrije Universiteit Brussel

More information about the gromacs.org_gmx-users mailing list