Localized operator partitioning method for electronic excitation energies in the time-dependent density functional formalism

Jayashree Nagesh; Michael J Frisch; Paul Brumer; Artur F Izmaylov

doi:10.1063/1.4972990

Localized operator partitioning method for electronic excitation energies in the time-dependent density functional formalism

J Chem Phys. 2016 Dec 28;145(24):244111. doi: 10.1063/1.4972990.

Authors

Jayashree Nagesh¹, Michael J Frisch², Paul Brumer¹, Artur F Izmaylov¹

Affiliations

¹ Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
² Gaussian, Inc., 340 Quinnipiac Street, Building 40, Wallingford, Connecticut 06492, USA.

PMID: 28049322
DOI: 10.1063/1.4972990

Abstract

We extend the localized operator partitioning method (LOPM) [J. Nagesh, A. F. Izmaylov, and P. Brumer, J. Chem. Phys. 142, 084114 (2015)] to the time-dependent density functional theory framework to partition molecular electronic energies of excited states in a rigorous manner. A molecular fragment is defined as a collection of atoms using Becke's atomic partitioning. A numerically efficient scheme for evaluating the fragment excitation energy is derived employing a resolution of the identity to preserve standard one- and two-electron integrals in the final expressions. The utility of this partitioning approach is demonstrated by examining several excited states of two bichromophoric compounds: 9-((1- naphthyl)- methyl)- anthracene and 4-((2- naphthyl)- methyl)- benzaldehyde. The LOPM is found to provide nontrivial insights into the nature of electronic energy localization that is not accessible using a simple density difference analysis.