[Wien] positive Fermi energy

[Peter Blaha]

> Perhaps my question is little stupid but
.As I know the Fermi energy delimit the highest occupied level, and as the energy levels are negative values.¶How we can get a positive Fermi energy?

The energy levels are only negative when one follows the convention that
you have an E-zero = 0  (at infinity from the atoms).

In a bandstructure we habe an "infinite" solid, thus NOT the same E-zero
as for atoms or molecules, but some internal E-zero.

                                      P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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