[Pw_forum] Smearing Functions

[Nicola Marzari]

On 06/07/2013 19:19, Ben Palmer wrote:
> Hi Everyone,
>
> I'm trying to understand more about smearing.  Are all smearing
> functions (Dirac, Fermi-Dirac, MP, MV) convoluted with whatever function
> is being smeared?
>
> Thank you
>
> Ben Palmer
> Student at University of Birmingham, UK


Hi Ben,


you convolute the density of states with a smearing function,
and the end result is that your variational functional (that was
the total energy E) becomes a free energy E-TS, with a mathematical
relation between smearing and temperature.

Have a look at S. de Gironcoli, PRB 51 6773 (1995) for the convolution,
and Chap 4 of http://theossrv1.epfl.ch/index.php?n=Main.Theses
for the relation between smearing and free energy.

				nicola



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-- 

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Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL