[CP2K:4836] R_CUTOFF vdWaals pair potential

[hut... at pci.uzh.ch]

Hi

where is this coming from
"in order to NOT exceed recommended 
     maximal value for this box size, namely half the box size"

we recommend to use a larger value.

regards

Juerg Hutter
 

--------------------------------------------------------------
Juerg Hutter                         Phone : ++41 44 635 4491
Physical Chemistry Institute   FAX   : ++41 44 635 6838
University of Zurich               E-mail:  hut... at pci.uzh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
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-----cp... at googlegroups.com wrote: -----
To: cp... at googlegroups.com
From: JanLos 
Sent by: cp... at googlegroups.com
Date: 12/17/2013 12:35PM
Subject: [CP2K:4836] R_CUTOFF vdWaals pair potential

                    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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