Dissociative photodetachment of H3O2−: a full-dimensional quantum dynamics study

Abstract

The transition state is a central concept of chemistry. Photoelectron–photofragment coincidence (PPC) spectroscopy has been proven as an attractive method to study the transition state dynamics. Within a state-of-the-art full-dimensional quantum mechanical model, the dissociative photodetachment dynamics of H₃O₂⁻ is investigated on accurate anion and neutral potential energy surfaces. The calculated PPC spectrum of H₃O₂⁻ agrees well with the experimental measurement. The dissociative product OH is exclusively populated on the ground vibrational state, implying the character of the spectator bond. In contrast, the product H₂O is predominantly populated in the ground and fundamental states of the symmetric and antisymmetric stretching modes, which is caused by the strong coupling between the antisymmetric motion of the transferred H atom in the transient intermediate [H₃O₂]* and both stretching modes of the product H₂O.