Aspects of Electron Correlation in Excited States

Résumé du livre

A correction to the Kohn-Sham eigenvalues based on Janak's theorem is used to calculate electron removal energies in a selection of atoms and molecules. The correction is found to give substantially better agreement with experiment than the bare LDA eigenvalues with significant computational effort. Excitation spectra for the dipole and quadrupole plasma oscillations in jel-lium spheres are obtained by the analytic continuation of imaginary time correlation functions computed by the fixed mode diffusion Monte Carlo method. The results provide a benchmark data to test approximate theories for excited states (e.g., the random phase approximation, time dependent density func-tional and the GW method). The stability of different phases of the three dimensional non-relativistic electron gas is analyzed using stochastic methods. At high electron densities