[gmx-users] free energy questions

[Mark Abraham]

MURAT CETINKAYA wrote:
> Hi,
> 
> I have a couple of questions about FE calculations. I am following the tutorial
> by Dill group for calculating the solvation FE of a non-standard residue. 
> 
> 1) Trivial questions first: It is advised to use PME with opls, is it possible
> to use PME in vacuo? As far as I know PME depends on periodicity, which is
> shut-off in vacuo.

PME requires periodicity, not that the periodic cell be "full". If it's 
shut off in vacuo, that's got nothing to do with it being in vacuo, and 
everything to do with how the system was configured.

Mark