title: Derivative Couplings between Time-Dependent Density Functional Theory Excited States in the Random-Phase Approximation Based on Pseudo-Wavefunctions: Behavior around Conical Intersections.
abstract: In this paper, we present a formalism for derivative couplings between time-dependent density functional theory (TD-DFT) excited states within the randomphase approximation (RPA) using analytic gradient theory. Our formalism is based on a pseudo-wavefunction approach in a companion paper (DOI 10.1021/jp505767b), and can be checked against finite-difference overlaps. Our approach recovers the correct properties of derivative couplings around a conical intersection (CI), which is a crucial prerequisite for any derivative coupling expression. As an example, we study the test case of protonated formaldimine (CH2NH2(+)).
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Qi
authors.initials: Q
authors.lastname: Ou
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Ethan C
authors.initials: EC
authors.lastname: Alguire
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Subotnik