[CP2K-user] [CP2K:7782] Re: R_CUTOFF vdWaals pair potential

[Austin clark]

Hi all,

I see that some SE codes do use the minimum image convention. Is the 
coulombic cutoff one of these, or can the cutoff be larger than one half of 
the cell length?

Thanks, 
Austin



On Monday, May 23, 2016 at 6:19:29 AM UTC-6, Guilherme da Silva wrote:
>
> 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: h... at chem.uzh.ch 
>> Winterthurerstrasse 190 
>> CH-8057 Zürich, Switzerland 
>> --------------------------------------------------------------- 
>>
>> -----c... at googlegroups.com wrote: -----To: cp2k <c... at googlegroups.com> 
>>
>> From: Guilherme da Silva 
>> Sent by: c... at googlegroups.com 
>> Date: 05/23/2016 01:42PM 
>> Cc: j... at science.ru.nl 
>> 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 
>>
>>     
>>
>>   
>>
>>
>>
>>
>>
>> -- 
>>
>> You received this message because you are subscribed to the Google Groups 
>> "cp2k" group. 
>>
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to cp... at googlegroups.com. 
>>
>> To post to this group, send email to c... at googlegroups.com. 
>>
>> Visit this group at https://groups.google.com/group/cp2k. 
>>
>> For more options, visit https://groups.google.com/d/optout. 
>>
>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20200421/69d931c4/attachment.htm>