[gmx-users] treatment of electrostatics in vaccum

[Sanku M]

Hi
  I need to run MD of a charged macromolecule in gas-phase or in vaccum. I was wondering if I use  no periodic boundary condition ( i.e. setting pbc=no  and ns_type=simple), can I get away with non-ewald type electrostatics method ( i.e. by using a very large cut-off like 3 or 4 nm for electrostatics  ) ? In this case, I wanted to minimize the computing expense associated with PME electrostatics. 


Thanks
Sanku