Electron energy loss and inelastic x-ray scattering cross sections from time-dependent density-functional perturbation theory

摘要: The Liouville-Lanczos approach to linear-response time-dependent density-functional theory is generalized so as encompass electron energy loss and inelastic x-ray scattering spectroscopies in periodic solids. computation of virtual orbitals the manipulation large matrices are avoided by adopting a representation response borrowed from (time-independent) density functional perturbation suitable Lanczos recursion scheme. latter allows bulk numerical work be performed at any given transferred momentum only once, for whole extended frequency range. complexity method thus greatly reduced, making function over wide range slightly more expensive than single standard ground-state calculation opening way computations systems unprecedented size complexity. Our validated on paradigmatic examples silicon aluminum, which both experimental theoretical results already exist literature.