[CP2K:4894] Re: Non-variational SCF energies

hut... at chem.uzh.ch hut... at chem.uzh.ch
Tue Jan 14 17:00:16 UTC 2014


the mixing produces a new energy but the code is still going on to
calculate part of the energy using the 'old' orbitals.
The calculated energy is therefore not variational. Only at convergence
you get a correct energy.


Juerg Hutter                         Phone : ++41 44 635 4491
Institut für Chemie                  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: Chris E 
Sent by: cp... at googlegroups.com
Date: 01/14/2014 05:29PM
Subject: [CP2K:4894] Re: Non-variational SCF energies

Marcella and Ari,

Thank you for the information. I have already tried tightening the EPS_SCF cutoff but not the EPS_DEFAULT. I will try that as well. 
Maybe I should review my DFT books to find this, but its worth asking: if tightened cutoffs produce the same results, is the higher energy calculated earlier in the SCF run a false energy due to mixing? Or does the mixing simply allow the energy to be non-variational? 

Thanks again,

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