[Pw_forum] VCA for positional disorder

[German Samolyuk]

Yes, you are right. My mistake.

German

On Apr 5, 2017 2:01 PM, "Novendra Novendra" <novendra.andra at gmail.com>
wrote:

Dear Dr. German Samolyuk,

Thank you for the detailed reply. I checked your example but I do not
understand how do you calculate the zed and config values according to the
vacancies? For mixture of Cu with 1/29 i was expecting the zed value to be
28.

Best regards,

Novendra Novendra

On Tue, Apr 4, 2017 at 3:29 PM German Samolyuk <samolyuk at gmail.com> wrote:

Dear Novendra Novendra,

The only way how to do it within pseudopotential method I found, was to
make pseudopotential with both zed and config values equal to fractional
number. For example, for Cu: zed=28.9, config='[Ar] 3d9.5 4s1.4 4p0.0'
corresponds to mixture of Cu with 1/29 vacancies.
It's not exactly the same as mixing with "empty" pspot, but more like rigid
band approximation for particular component.
If you need do do something more accurate, probably, one of the CPA KKR
packages will be more appropriate.
One more comment regarding modeling vacancies with VCA. You probably should
remember that even in closed packed structures like most of the metals
relaxation of surrounding vacancy atoms positions is significant. This
effect is not included within VCA approach.

Best,

German Samolyuk

ORNL

On Mon, Apr 3, 2017 at 2:34 PM, Novendra Novendra <novendra.andra at gmail.com>
wrote:

Dear QE developers,

I am trying to prepare input file for a system with a positional disorder.
I have seen some example where VCA can be applied for system with
substitional disorder, where in that case a virtual PP can be prepared by
mixing PP of different elements. In the case of positional disorder, is it
possible to prepare a virtual PP by mixing with an "empty" PP?

Thank you,

Novendra Novendra
Ph.D Student,
Department of Chemical Engineering & Materials Science
University of California, Davis


_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org
http://pwscf.org/mailman/listinfo/pw_forum


_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org
http://pwscf.org/mailman/listinfo/pw_forum


_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org
http://pwscf.org/mailman/listinfo/pw_forum
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20170412/6cea288b/attachment.html>