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Long-range excitations in time-dependent density functional theory

Neepa T. Maitra·David G. Tempel
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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.

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Neepa T. Maitra, David G. Tempel. 2006-08-07. Long-range excitations in time-dependent density functional theory. https://doi.org/10.1063/1.2387951

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