[CP2K:5710] Possible bug in DFT-D3

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

Hi

yes, this is a bug. The C9 term as implemented is not invariant
to translations. I try to find a fix - fighting with unique
triple lists.

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: yakutovich 
Sent by: cp... at googlegroups.com
Date: 10/07/2014 11:17AM
Subject: Re: [CP2K:5710] Possible bug in DFT-D3

Dear Juerg, 

Sorry that I didn't post the coordinates file, now you can find it in the attachement (p.xyz).

Following you suggestion I  added the PRINT section in the DFTD3 part of input. Please find enclosed files 20-vacuum-PROJ-1_0.dftd and 40-vacuum-PROJ-1_0.dftd.

I also tried an another thing: from DFTD3 section I removed the C9 tem. Then the vdW energies become the same for both structures (see  20-vacuum-no-C9-PROJ-1_0.dftd  and  40-vacuum-no-C9-PROJ-1_0.dftd)

So apparently there is a bug in calculating C9 term.

Best regards
Sasha


On Tuesday, October 7, 2014 9:52:27 AM UTC+2, jgh wrote: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)   
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[attachment "20-vacuum-no-C9-PROJ-1_0.dftd" removed by Jürg Hutter/at/UZH]
[attachment "20-vacuum-PROJ-1_0.dftd" removed by Jürg Hutter/at/UZH]
[attachment "40-vacuum-no-C9-PROJ-1_0.dftd" removed by Jürg Hutter/at/UZH]
[attachment "40-vacuum-PROJ-1_0.dftd" removed by Jürg Hutter/at/UZH]
[attachment "p.xyz" removed by Jürg Hutter/at/UZH]