This set of slides explains to the users the concept of valence vs. core electrons, the implications of the adiabatic approximation on the separation of the total Hamiltonian of the system and the mean-field approximation used in ab initio bandstructure approaches. It then gives systematic categorization of the ab initio and semiempirical electronic structure calculation methods. Finally it discusses the advantages and the disadvantages of the semiempirical methods (Empirical Pseudopotentials Method, Tight-Binding Method and k.p Method). In summary, this set of slides explains under what assumptions we can separate the total Hamiltonian of the system into a lattice part, electronic part and electron-phonon interaction that is usualy treated perturbatively as a scattering process.
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