[Pw_forum] which is the local potential

[Stefano Baroni]

one further reason why the bare+Hartree potential should be used for  
estimating the value of the potential in the vacuum far from a surface  
(or from a molecule), even if the simple LDA is used, is that the  
exchange potential tends to zero as (\rho)^{1\over 3}, while the  
Hartree+bare potential tends to zero as \rho, hence faster.
SB

On Nov 1, 2009, at 9:11 AM, Paolo Giannozzi wrote:

>
> On Oct 31, 2009, at 10:23 , wujianchun wrote:
>
>> The question is which one, 1 total potential V_bare+V_H+V_xc,
>> 11 the V_bare+V_H potential or 12 the electric field potential in
>> plot_num, corresponds the above-mentioned "local potentials"?
>
> definitely not 12; the local potential is 1. The case "11" is useful
> to calculate the average potential far from a surface (e.g. for
> work function calculation) since the XC potential has often a
> nasty behavior when the charge density vanishes
>
>> PS: which is the unit of the potentials in the outfiles, eV or Ry?
>
> Ry
>
> P.
> ---
> Paolo Giannozzi, Dept of Physics, University of Udine
> via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
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http://stefano.baroni.me [+39] 040 3787 406 (tel) -528 (fax) /  
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