Problem with large CUTOFFs for non-local vdW functionals

[Jan Elsner]

Dear all, 

When I try to use a large CUTOFF (MGRID section) with non-local vdW functionals (I have tried optPBE, optB88 and vdW-DF2), the program seems unable to calculate the vdW energy and I get a CPASSERT failed error. For my particular system (periodic rubrene molecular crystal), the program runs fine with CUTOFF 1100 Ry, but fails for CUTOFF 1200 Ry. I note that the CUTOFF at which the program crashes is cell-size dependent e.g. if I use a smaller CELL_REF (or no CELL_REF), I can go to higher CUTOFFs before the program crashes. 

I attach input and output files using optPBE for the cases: (i) CUTOFF 1100 Ry, run succeeds and (ii) CUTOFF 1200 Ry, run fails.

It would be great to know why these functionals cannot cope with large CUTOFFs.

Best wishes, 

Jan

[hut...@chem.uzh.ch]

Hi

Nonlocal vdW functionals make use of the precomputed kernel table.
This table was calculated with a maximum cutoff and this is checked
in CP2K to avoid unphysical extrapolation.
If you need such high cutoffs, you have to generate another
kernel file. This is a file that was generated from Quantum Espresso.

regards

Juerg Hutter
--------------------------------------------------------------
Juerg Hutter Phone : ++41 44 635 4491
Institut für Chemie C FAX : ++41 44 635 6838
Universität Zürich E-mail: hut...@chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

-----cp...@googlegroups.com wrote: -----
To: "cp2k" <cp...@googlegroups.com>
From: "Jan Elsner"
Sent by: cp...@googlegroups.com
Date: 06/03/2020 02:46PM
Subject: [CP2K:13438] Problem with large CUTOFFs for non-local vdW functionals

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[attachment "fail-cutoff-1200.inp" removed by Jürg Hutter/at/UZH]
[attachment "fail-cutoff-1200.out" removed by Jürg Hutter/at/UZH]
[attachment "subsys.include" removed by Jürg Hutter/at/UZH]
[attachment "success-cutoff-1100.inp" removed by Jürg Hutter/at/UZH]
[attachment "success-cutoff-1100.out" removed by Jürg Hutter/at/UZH]

[Jan Elsner]

Cheers!

Jan

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