[gmx-users] Making two defaults sections compatible

[Steven Kirk]

Hello,

I'm using a macromolecule with the OPLS-AA force field, solvated with 
SSWM4-DP polarizable water (many thanks to DvS for this). The .itp file 
for the polarizable water has a [defaults] line that looks like:

[ defaults ]
LJ      Geometric

whereas when the OPLS-AA forcefield .itp files are read in, they contain 
a defaults section that looks like this:

[ defaults ]
; nbfunc        comb-rule       gen-pairs       fudgeLJ fudgeQQ
1               3               yes             0.5     0.5

and hence grompp complains about two [defaults] sections.

I know comb-rule 3 means geometric averages of LJ parameters, but I'm 
wondering about the compatibility of the 'gen-pairs', 'fudgeLJ' and 
'fudgeQQ' parameters.

Can anyone suggest a single defaults line that would be compatible with 
both of these ? Could I safely use ONLY the OPLS-AA defaults line 
without breaking SSWM4-DP?

Many thanks,
Steve Kirk

-- 
Dr. Steven R. Kirk           <Steven.Kirk at hv.se, S.R.Kirk at physics.org>
Dept. of Technology, Mathematics & Computer Science  (P)+46 520 223215
University West                                      (F)+46 520 223299
P.O. Box 957 Trollhattan 461 29 SWEDEN       http://taconet.webhop.org