[CP2K:5703] Possible bug in DFT-D3

[hut... at chem.uzh.ch]

Hi

I cannot reproduce your problem using a simple input.
Can you either send the coordinate file or rerun the
jobs with additional output for the DFTD3 section:
            VERBOSE_OUTPUT
            &PRINT_DFTD
            &END

By sending reproducible inputs/output you make our life easier.

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
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

-----cp... at googlegroups.com wrote: -----
To: cp... at googlegroups.com
From: Leopold Talirz 
Sent by: cp... at googlegroups.com
Date: 10/06/2014 04:17PM
Subject: [CP2K:5703] Possible bug in DFT-D3

        Dear all,
 

a colleague in my lab found an unexpected dependence of the DFT-D3 dispersion energy on the amount of vacuum in a slab calculation, which could indicate a bug in the DFT-D3 implementation.
 

Here the message from Sasha:
I have a slab geometry for a slab that is ~20 A thick (less than 20) and I perforrm a fully periodic calculation.
 To test the convergence of the vacuum region i performed ENERGY calculations with a cell of 40 A  (so 20 A of vacuum) and, afterwards, the same ENERGY calculation with a cell thickness of 60A (so 40 A of vacuum).
 

 I did define R_CUTOFF for the VDW as 8 A, i.e. less than half of the vacuum region. I was therefore expecting the dispersion energy to be exactly the same (?).
 

 The ENERGY calculations for the SAME geometry (file p.xyz) give rise to a difference of 1.8eV in the dispersion energy term for the DFT-D3 calculation, when i change the cell size.
 I repeated the same calculations with DFT-D2 and in this case there is no difference in the dispersion energy (as I would have expected).
 

 In the tar file you can find the input that I used for the four different calculations (DFT-D3 with 20 and 40 A of vacuum  and DFT-D2 same two cases) as well as output files and the geometry p.xyz.
 Does anybody have an idea on what could be wrong?

 

 Thanks in advance for your help
 

Kind regards,

Sasha (and Leopold)  
  -- 
 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 cp2k+uns... at googlegroups.com.
 To post to this group, send email to cp... at googlegroups.com.
 Visit this group at http://groups.google.com/group/cp2k.
 For more options, visit https://groups.google.com/d/optout.
 

[attachment "question.tar.gz" removed by Jürg Hutter/at/UZH]