%AZhou, Chen%AGagliardi, Laura%ATruhlar, Donald%BJournal Name: Physical Chemistry Chemical Physics; Journal Volume: 21; Journal Issue: 25
%D2019%I
%JJournal Name: Physical Chemistry Chemical Physics; Journal Volume: 21; Journal Issue: 25
%K
%MOSTI ID: 10168432
%PMedium: X; Size: 13486 to 13493
%TState-interaction pair density functional theory for locally avoided crossings of potential energy surfaces in methylamine
%XThe strong couplings between electronic states in conical intersection regions are among the most challenging problems in quantum chemistry. XMS-CASPT2, a second-order multireference quasidegenerate perturbation theory, has been successful in describing potential energy surfaces near the conical intersections. We have recently proposed a less expensive method for this problem, namely state-interaction pair-density functional theory (SI-PDFT), which considers the coupling between electronic states described by multiconfiguration pair-density functional theory (MC-PDFT). Here we test the accuracy of SI-PDFT for closely coupled potential energy surfaces of methylamine along five different reaction paths for N–H bond fission. We choose paths that pass close to a conical intersection of the ground and first excited states. We find that SI-PDFT predicts potential energy curves and energy splittings near the locally avoided crossing in close proximity to those obtained by XMS-CASPT2. This validates the method for application to photochemical simulations.
%0Journal Article