R_CUTOFF vdWaals pair potential

[Guilherme da Silva]

Hi,

I know that this one is a bit too old, but I have a similar doubt.

I think he argues about the possibility of high r_cutoff values to violate 
the minimum-image convention. Is that simply not true?

And if it does violate, have anyone some answer about what would be worse: 
to violate the mic or to not compute the dispersion correction in an 
appropriate range?

Regards,

Em terça-feira, 17 de dezembro de 2013 09:35:30 UTC-2, JanLos escreveu:
>
> Dear CP2K developpers,
> I  was wondering about the comment in the section 
> "FORCE_EVAL/DFT/XC/VDW_POTENTIAL/PAIR_POTENTIAL/R_CUTOFF",
> saying "*The cutoff will be 2 times this value". *
> If I stick to the default value of 10.06 Angstrom for this parameter, 
> the cut-off will be 20.12 Angstrom, which is pretty large, but OK. 
> If this is really what is applied, then it would imply that for a cubic 
> simulation 
> box of 20 A cube with periodic boundary conditions, R_CUTOFF should not 
> be set larger than 5.0 Angstrom in order to NOT exceed recommended 
> maximal value for this box size, namely half the box size. Do I see this 
> correctly ?
> It's just that the comment " *The cutoff will be 2 times this value*" 
> confuses me, 
> asking myself why this input parameter been defined in this way.
> By the way, is the minimal image convention applied for the calculation
> of these interactions ?
>                                                                
> Regards,                  Jan Los
>
>
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