[Pw_forum] Noncollinear magnetization and spin orbit coupling problem on Energy convergence and Spin

[Giovani Faccin]

Dear Xiao,

I'm didn't catch the entire discussion thread, so first of all, sorry if
this might be redundant. Anyway, looking at your input file, three things
came to mind:

1 - Small cutoff radius (30 Ry / 300 Ry)
2 - Small number of k-points. (3 3 1)
3 - Perhaps, a too large degauss value (0.05 Ry).

So, just in case, I should ask: are those values well converged for all
those pseudopotentials you are using?

If unsure, one simple way to test it is to evaluate dimers of each material
(O2, Se2 etc.) and run scf tests varying those 3 parameters, to see how the
total energy behaves. Once you find a setup that works on all the elements
simultaneously, then you can come back to the full system, using this setup
as a starting point for further tests. As a hint, for some  magnetic
phenomena a precision of at least 10^-2 Ry in total energy convergence can
be relevant.

Regards,

-- 
Giovani M. Faccin <https://sites.google.com/site/faccingiovani/>
CPPP / UFMS - Brazil
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20140302/2302657d/attachment.html>