Model Hamiltonians and How to Determine their Parameters
It is straightforward to write down the Hamiltonian for the electrons in molecules or solids within the Born-Oppenheimer approximation for the nuclei. Unfortunately the resulting electronic many-body problem is notoriously hard to solve. The idea of mean field theory has therefore very early been used in attempts to perform reasonable calculations for the properties of atoms and molecules.1 In quantum chemistry a Hartree-Fock calculation is the usual starting point for configuration interaction (CI) calculations, which can yield very accurate results for small molecules. As this technique is not very well suited for solids, the Hohenberg-Kohn-Sham density functional theory (DFT) represented a major step forward.2 These authors showed that the calculation of ground state properties can be formally exactly reduced to a problem of non-interacting electrons in an effective potential veff.
KeywordsSpectral Function Core Level Spectrum Anderson Impurity Model Screen Mechanism Anderson Impurity
Unable to display preview. Download preview PDF.
- 3.U. von Barth and A.R. Williams, in “Theory of the Inhomogeneous Electron Gas”, Eds. S. Lundqvist and N.H. March (Plenum, New York, 1983).Google Scholar
- 8a.K. Schönhainmer and O. Gurmarsson, Z. Phys. B30:297 (1987).Google Scholar
- 16.O. Gunnarsson and K. Schönhammer, Handbook on the Physics and Chemistry of Rare Earths (eds. K. Gschneider, L. Eyring and S. Hüfner), Vol. 10, North-Holland, Amsterdam (1986).Google Scholar