Next-generation quantum theory of atoms in molecules for the ground and excited state of DHCL

Abstract

The factors underlying two possible pathways for the Dihydrocostunolide (DHCL) photochemical ring-opening reaction were investigated; the first pathway returned to the ring-closed conformation of the reactant and the second pathway progressed to the ring-opened product. High-level multi-reference DFT methods were used to optimize the two pathways and the density was analyzed using QTAIM and the stress tensor. Oscillations in the chemical character of the fissile bond were found for the first pathway before and after the conical intersection that steered the reaction back to reactant. Conversely, this behavior was absent for the second pathway that led forward to the product.