[CP2K:9441] Re: Hybrid functional calculation results show large difference with VASP

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

Hi

I would first try a larger ADMM basis, e.g. pFIT3.

The increase in CPU time for a full exchange calculation with
MOLOPT basis sets can be 100x - 1000x.

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
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-----cp... at googlegroups.com wrote: -----To: cp2k <cp... at googlegroups.com>
From: Xiaoming Wang 
Sent by: cp... at googlegroups.com
Date: 09/19/2017 04:46PM
Subject: [CP2K:9441] Re: Hybrid functional calculation results show large difference with VASP

Hi Marcella,
What do you mean by the 'smaller version'? If you are meaning a smaller basis set for ABS, I did the test. To my surprise, the results don't change much when I go to the smallest ABS, say cFIT3 for Cl, cFIT9 for Ag and In, cFIT7 for Cs. Is this behavior reasonable? 
Without ADMM, it seems that the computation would take extremely long time with the same cpu cores. With ADMM, I can finish the calculation within couple of minutes. However, without ADMM, it has taken me almost one hour and the first OT step hasn't even appear in the output. Does this sounds reasonable as well?
Best,Xiaoming 

On Tuesday, September 19, 2017 at 4:58:43 AM UTC-4, Marcella Iannuzzi wrote:Hi, 
Can you test your system without ADMM? (maybe a smaller version of it)You should compare the electronic properties obtained with and without ADMM to verify whether the problems is there or somewhere else.RegardsMarcella

On Tuesday, September 19, 2017 at 8:23:59 AM UTC+2, Xiaoming Wang wrote:Hi,
I checked the convergence of the primary basis size. To be specific, I compared the DZVP and TZVP basis sets. The difference of the PBE band gap is within 0.01 eV.  The PBE0 band gap without coulomb trunction also shows small difference, say ~0.01 eV. The band gap variation by coulomb truncation as in PBE0-TC-LRC scheme is larger, say 0.05 eV, but still not too much.  
Any other advice?
Best,Xiaoming






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