[Pw_forum] high energy bands

Paolo Giannozzi giannozz at nest.sns.it
Tue Feb 19 16:43:54 CET 2008

alan chen wrote:

> I am just curious to ask whether those bands (their eigenvalues and 
> eigenvectors) with very high energies (~15 eV above Fermi level) are 
> reliable or not.

difficult to say. Pseudopotentials have a limited energy range of
good transferability (but not so limited: a few Ry around the
reference energy). They may have ghosts states at high energies
(where nobody will notice except you). The higher the energy,
the more your bands will be free-electron-like and the less the
pseudopotential will be important, though.

Paolo Giannozzi, Democritos and University of Udine, Italy

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