Final State Resolved Quantum Predissociation Dynamics of SO2(C1B2) and Its Isotopomers via a Crossing with a Singlet Repulsive State

TL;DR

This study investigates the quantum dynamics of SO2 predissociation, revealing how internal state distributions of fragments depend on initial states and photon energy, using high-level ab initio potential energy surfaces.

Contribution

It provides a detailed quantum mechanical analysis of SO2 predissociation, including isotopomers, on an accurate PES with conical intersections, which is novel in the field.

Findings

Significant rotational and vibrational excitations in SO fragments.

Fragment internal states depend strongly on predissociative vibronic states.

Excitations increase with photon energy.

Abstract

The fragmentation dynamics of predissociative SO2(C1B2) is investigated on an accurate adiabatic potential energy surface (PES) determined from high level ab initio data. This singlet PES features non-C2v equilibrium geometries for SO2, which are separated from the SO + O dissociation limit by a barrier resulting from a conical intersection with a repulsive singlet state. The ro-vibrational state distribution of the SO fragment is determined quantum mechanically for many predissociative states of several sulfur isotopomers of SO2. Significant rotational and vibrational excitations are found in the SO fragment. It is shown that these fragment internal state distributions are strongly dependent on the predissociative vibronic states, and the excitation typically increases with the photon energy.