Long-range excitations in time-dependent density functional theory
Abstract
Adiabatic time-dependent density functional theory fails for excitations of a heteroatomic molecule composed of two open-shell fragments at large separation. Strong frequency-dependence of the exchange-correlation kernel is necessary for both local and charge-transfer excitations. The root of this is static correlation created by the step in the exact Kohn-Sham ground-state potential between the two fragments. An approximate non-empirical kernel is derived for excited molecular dissociation curves at large separation. Our result is also relevant for the usual local and semi-local approximations for the ground-state potential, as static correlation there arises from the coalescence of the highest occupied and lowest unoccupied orbital energies as the molecule dissociates.
Cite
@article{arxiv.cond-mat/0510588,
title = {Long-range excitations in time-dependent density functional theory},
author = {Neepa T. Maitra and David G. Tempel},
journal= {arXiv preprint arXiv:cond-mat/0510588},
year = {2009}
}
Comments
7 pages, 2 figures