[Pw_forum] Which Fermi level is right?

[Nicola Marzari]

Dear All,

an additional comment here - all smearing schemes will converge
to the same identical result in the limit of zero smearing/temperature,
and accurate sampling.

The tetrahedron method is not a smearing scheme, but again all correct
calculations hsould converge to the same value.

This has been often repeated, but it is worthwhile testing all
of this on one's own, to figure out what is really happening.

			nicola




lan haiping wrote:
> Dear  George,
> I am not familiar with all these smearing scheme, and just try to 
> explain as far as i know.
> When we do calculation with "smearing",  fractional occupations are allowed.
> For different smearing scheme, the occupation functions are defined 
> differently.
> So, it should be nonsense to discuss the absolute  values of fermi 
> energy obtained from different smearing schemes.

-- 
---------------------------------------------------------------------
Prof Nicola Marzari   Department of Materials Science and Engineering
13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu