Excitations in time-dependent density-functional theory
arXiv:cond-mat/0203027 · doi:10.1103/PhysRevLett.90.043005
Abstract
An approximate solution to the time-dependent density functional theory (TDDFT) response equations for finite systems is developed, yielding corrections to the single-pole approximation. These explain why allowed Kohn-Sham transition frequencies and oscillator strengths are usually good approximations to the true values, and why sometimes they are not. The approximation yields simple expressions for Görling-Levy perturbation theory results, and a method for estimating expectation values of the unknown exchange-correlation kernel.
4 pages, 1 table