[Wien] Structural optimization, volume optimization

[Fecher, Gerhard]

Dear Lyudmila,
then my trivial answer would be: The wrong structure was used if you find any other that has a lower energy.

My fear, this is very often the case.

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."

====================================
Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden
________________________________________
Von: Wien [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Lyudmila Dobysheva [lyuka17 at mail.ru]
Gesendet: Donnerstag, 3. Mai 2018 11:59
An: wien at zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] Structural optimization, volume optimization

02.05.2018 11:20, Fecher, Gerhard wrote:
> To optimize the structure you need
> - optimization of the lattice parameters (a,b,c, alpha, beta, gamma, or a set out of them depending on the space group)
> - optimization of the atomic positions (if the sites have free parameters)

I'd like to add here that, when a site does not have free parameters, it
can be a maximum in energy, not a minimum; and if to be very meticulous
one should check this also.

--
Lyudmila Dobysheva
------------------
Physics-Techn.Institute,
Udmurt Federal Research Center, Ural Br. of Rus.Ac.Sci.
426000 Izhevsk Kirov str. 132
Russia
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