Density-matrix propagation driven by semiclassical correlation

Peter Elliott, Neepa T. Maitra

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Methods based on propagation of the one-body reduced density-matrix hold much promise for the simulation of correlated many-electron dynamics far from equilibrium, but difficulties with finding good approximations for the interaction term in its equation of motion have so far impeded their application. These difficulties include the violation of fundamental physical principles such as energy conservation, positivity conditions on the density, or unchanging natural orbital occupation numbers. We review some of the recent efforts to confront these problems, and explore a semiclassical approximation for electron correlation coupled to time-dependent Hartree-Fock propagation. We find that this approach captures changing occupation numbers, and excitations to doubly-excited states, improving over TDHF and adiabatic approximations in density-matrix propagation. However, it does not guarantee N-representability of the density-matrix, consequently resulting sometimes in violation of positivity conditions, even though a purely semiclassical treatment preserves these conditions.

Original languageEnglish (US)
Pages (from-to)772-783
Number of pages12
JournalInternational Journal of Quantum Chemistry
Volume116
Issue number10
DOIs
StatePublished - May 15 2016

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All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

Keywords

  • Frozen Gaussian
  • double excitations
  • reduced density matrix
  • semiclassical methods
  • time dependent density matrix functional theory

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