[Wien] oscillation in charge

Laurence Marks L-marks at northwestern.edu
Sun Mar 9 23:29:39 CET 2008


This is not a trivial problem, and does not have a trivial answer. The
key problem is that with straight GGA the Hamiltonian for isolated
transition metal atoms is not very good, and the problem may be
discontinuous and/or very (very) ill-posed and ill-conditioned near
the solution -- and the energy you get will not be very good. The best
that you can do with the current version of Wien2k is probably to
switch to Pratt mixing with a fairly small value (e.g. 0.02) and be
VERY careful. Do it in part by hand (run a few cycles only each time
and check). Use of TEMP smearing can help a bit.

Your box maybe a bit small (if that is the size in a.u.) although that
won't help the convergence.

On Sun, Mar 9, 2008 at 5:17 PM, hazem salem <salemhadihazem at yahoo.com> wrote:
>
> Dear Wien users,
>                          I'm doing spin-polarized calculations for isolated
> iridium atom in a box of dimensions 12, 12, 12
> there is no convergence obtained and the charge is oscillating. This is also
> besides the WARNING in the total energy.
> Can someone tell me why do I have such a problem.
>
> Thank you
> Hazem
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-- 
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60208, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
Web: www.numis.northwestern.edu
Commission on Electron Diffraction of IUCR
www.numis.northwestern.edu/IUCR_CED


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