Conical intersection induced by the Jahn-Teller effect in molecular dynamic simulations

This study elucidates the role of a conical intersection induced by the Jahn-Teller effect (CIJT) in modulating the reactivity of the oxygen-methane reaction, a prototypical system involving excited states. Using ab initio calculations, we constructed a diabatic potential energy matrix to characterize the molecular structure at the CIJT and its associated twin saddle points. These structural features orchestrate population transfer between electronic states, with the CIJT serving as a critical junction for interstate transitions. It involves an interplay between two excited states and introduces a geometric phase effect, resulting in destructive interference that manifests as distinct nodal patterns when a wave packet is launched through the system. These characteristics significantly influence the reaction pathway, altering the accessibility of competing electronic states and thus modulating reactivity. Our findings thus establish a direct connection between JT induced topology and nonadiabatic reactivity, highlighting a mechanism by which conical intersections actively control excited-state dynamics in reactive intermediates.