[gmx-users] pressure in NPT and NVT

[Nilesh Dhumal]

Hello,

I am using NPT simulation for water - spce model (opls-aa force field).
I have the reference pressure set at ref_p = 1.0 bar.
I checked the average pressure using g_energy and it is 2.81972 bar.

Why there increase in pressure?



For NVT simulatin I get the value around average pressure 710.685 bar.

I am running the simulation at 295 k and  average temp. is 294.98 K which
look ok.


Can you tell why there is increase in pressure for NPT and  why there is
so high value of pressure in NVT.

I am using gromacs version 4.0.7.

Thanks

Nilesh