[gmx-users] Problems with TIP4P

[Justin MacCallum]

Hi,

has anyone been able to get TIP4P to work with OPLSAA. I've made all of
the relevant changes to tip4pgmx.itp to make it work with OPLSAA. Grompp
runs without errors, however when I actually run the simulation the box
blows up, and the Colomb energy (both LR and SR) is zero! I'm using
0.9/1.4 twin-range cutoffs. Any ideas?

I've attached the itp file below:

Cheers,
Justin

[ moleculetype ]
; molname       nrexcl
SOL             1

[ atoms ]
; id    at type         res nr  residu name     at name         cg nr
charge  mass
1       OPLS_113        1       SOL             OW1             1      
0       15.9994
2       OPLS_114        1       SOL             HW2             1      
0.52    1.008
3       OPLS_114        1       SOL             HW3             1      
0.52    1.008
4       OPLS_115        1       SOL             MW4             1     
-1.04    0.000

[ settles ]
; i     funct   doh     dhh
1       1       0.09572 0.15139

[ dummies3 ]
; Dummy from                    funct   a               b
4       1       2       3       1       0.128012065     0.128012065

[ exclusions ]
1       2       3       4
2       1       3       4
3       1       2       4
4       1       2       3