@article{338,
  keywords = {paper},
  author = {Fabien Bruneval and Francesco Sottile and Olevano V and Lucia Reining},
  title = {Beyond time-dependent exact exchange: The need for long-range correlation},
  abstract = {In the description of the interaction between electrons beyond the classical Hartree picture, bare exchange often yields a leading contribution. Here we discuss its effect on optical spectra of solids, comparing three different frameworks: time-dependent Hartree-Fock, a recently introduced combined density-functional and Green\textquoterights function approaches applied to the bare exchange self-energy, and time-dependent exact exchange within time-dependent density-functional theory (TD-EXX). We show that these three approximations give rise to identical excitonic effects in solids; these effects are drastically overestimated for semiconductors. They are partially compensated by the usual overestimation of the quasiparticle band gap within Hartree-Fock. The physics that lacks in these approaches can be formulated as screening. We show that the introduction of screening in TD-EXX indeed leads to a formulation that is equivalent to previously proposed functionals derived from many-body perturbation theory. It can be simulated by reducing the long-range part of the Coulomb interaction: this produces absorption spectra of semiconductors in good agreement with experiment. (c) 2006 American Institute of Physics.},
  year = {2006},
  journal = {J. Chem. Phys.},
  volume = {124},
  number = {14},
  pages = {144113},
  month = {APR 14},
  publisher = {AMER INST PHYSICS},
  address = {CIRCULATION \& FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA},
  url = {http://dx.doi.org/10.1063/1.2186996},
  doi = {10.1063/1.2186996},
}