[CP2K:7782] Re: R_CUTOFF vdWaals pair potential

[Guilherme da Silva]

Hi,

Thanks for answering so fast!

regards,

Guilherme

Em segunda-feira, 23 de maio de 2016 08:51:04 UTC-3, jgh escreveu:
>
> Hi 
>
> In almost all parts of the program (exceptions are some DFTB and SE codes, 
> and maybe HFX) CP2K does not use the minimum image convention. It is save 
> to use 
> interaction ranges that are larger than the simulation box. 
>
> regards 
>
> Juerg 
> -------------------------------------------------------------- 
> Juerg Hutter                         Phone : ++41 44 635 4491 
> Institut für Chemie C                FAX   : ++41 44 635 6838 
> Universität Zürich                   E-mail: hut... at chem.uzh.ch 
> <javascript:> 
> Winterthurerstrasse 190 
> CH-8057 Zürich, Switzerland 
> --------------------------------------------------------------- 
>
> -----cp... at googlegroups.com <javascript:> wrote: -----To: cp2k <
> cp... at googlegroups.com <javascript:>> 
> From: Guilherme da Silva 
> Sent by: cp... at googlegroups.com <javascript:> 
> Date: 05/23/2016 01:42PM 
> Cc: j.... at science.ru.nl <javascript:> 
> Subject: [CP2K:7782] Re: R_CUTOFF vdWaals pair potential 
>
> 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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