[gmx-users] Water Potential Energy

[Mark Abraham]

On 14/06/2011 4:18 AM, Rini Gupta wrote:
> Dear gmx-users,
>
> I am using GROMACS 4.5.4 to run a pure water system using SPC/E model
> containing 32000 molecules. I have done the equilibration for 2 ns 
> followed by production run of 5 ns using NPT ensemble at 300K.
> I am using PME for treating electrostatic interactions (cut-off 0.9 nm).
> My question is Potential Energy of the system I am getting is -46.7 
> kJ/mol while literature value is -41.5 kJ/mol.
> Can anyone please tell me why this discrepancy is coming?

PE is size- and method-dependent. Are you reproducing the conditions 
exactly?

Mark