[DFTB-Plus-User] band energy vs total electronic energy

[Bálint Aradi]

Dear James,

> Naively I would assume that total energy = band energy + repulsive
> energy. The total electronic energy does not match the band energy. Can
> you explain what the difference between band energy is compared to total
> electronic energy?

The total electronic energy is composed as a sum of the non-SCC and SCC
contributions (and eventually other terms like spin polarization).
The non-scc contribution is Tr[Rho H0], with H0 being the non-scc
Hamiltonian and Rho the density matrix. The SCC-contribution is
calculated based on the net charges of the atoms.

You can find further details in any DFTB-method paper, for example in

http://rsta.royalsocietypublishing.org/content/372/2011/20120483

Best regards,

Bálint

-- 
Dr. Bálint Aradi
Bremen Center for Computational Materials Science, University of Bremen
http://www.bccms.uni-bremen.de/cms/people/b-aradi/


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