Intermediate photofragment distributions as probes of non-adiabatic dynamics at conical intersections: application to the Hartley band of ozone

Abstract

Quantum dynamics at a reactive two-state conical intersection lying outside the Franck–Condon zone is studied for a prototypical reaction of ultraviolet photodissociation of ozone in the Hartley band. The focus is on the vibrational distributions in the two electronic states at intermediate interfragment distances near the intersection. Such intermediate distributions of strongly interacting photofragments contain unique information on the location and shape of the conical intersection. Multidimensional Landau–Zener modeling provides a framework to reverse engineer the molecular geometry-dependent Massey parameter of the intersection from the intermediate distributions. The conceptual approach is demonstrated for the intermediate O–O bond stretch distributions which become strongly inverted on adiabatic passage through the intersection. It is further demonstrated that intermediate distributions can be reconstructed from the photoemission spectrum of the dissociating molecule. The illustration, given using quantum mechanical calculations of resonance Raman profiles for ozone, completes a practicable cycle of conversion of intermediate distributions into topographic features of the conical intersection.