[gmx-users] treatment of electrostatics in vaccum

[Erik Marklund]

Hi,

Cut-offs can also be more efficient, depending on the size and charge of your molecule. A periodic box that is large enough to keep periodicity artefacts negligible in vacuo may involve a huge PME grid.

Kind regards,
Erik

On 5 Aug 2014, at 18:17, Justin Lemkul <jalemkul at vt.edu> wrote:

> 
> 
> On 8/5/14, 7:39 AM, Sanku M wrote:
>> 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.
>> 
> 
> Infinite cutoffs would be more common.
> 
> -Justin
> 
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