title: Implementation of the Bethe-Salpeter equation in the TURBOMOLE program.
abstract: A software update solving the Bethe-Salpeter equation (BSE) is reported for the ESCF module of the TURBOMOLE program for the theoretical description of electronically excited states of atoms and molecules. A resolution-of-the-identity (RI) approximation is used for all two-electron electron-repulsion integrals that are required for solving the equation. Symmetry is utilized for the point group D2hand its subgroups, and the BSE approach can be applied in either a spin-restricted or a spin-unrestricted Kohn-Sham formalism. Triplet as well as singlet excited states of closed-shell atoms and molecules can be treated in the spin-restricted formalism. As a side product, the present software update also allows for the application of the RI approximation to the Hartree-Fock exchange contribution that occurs when a hybrid functional is used in time-dependent density-functional theory. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute of Physical Chemistry, P.O. Box 6980, Karlsruhe, D-76049, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Krause
authors.affiliation: Karlsruhe Institute of Technology (KIT), Institute of Physical Chemistry, P.O. Box 6980, Karlsruhe, D-76049, Germany.
authors.forename: Wim
authors.initials: W
authors.lastname: Klopper
keywords: Bethe−Salpeter equation; electronic excitation energy; exchange interaction; resolution-of-the-identity approximation; time-dependent density-functional theory