A box of water explodes in the y direction

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1

GROMACS version: - 2020.1
GROMACS modification: No

I’m running a simulation where I have a box with water in the dimensions:
1.7 X 2.5 X 2.7
with 377 molecules. I did the optimization with optmize.mdp and then I did the optimization with NPT.mdp putting the temperature at 300K. But the box explodes in the y direction. I tried lowering the pressure too but got the same result. Does anyone have any suggestions to resolve this error?

Some input details:
NPT.mdp: dt = 0.002, nsteps = 50000
rlist = rcoulomb = rvdw = 0.01
tau_p = 5.0
compressibility = 0 4.5e-5 0 0 0 0
ref_p = 0 1 0 0 0 0
periodic_molecules = yes

2

These cutoffs are about 100x too short. You won’t get anything physically sensible with this nonbonded setup.