Photodissociation of permanganate (MnO4−) produces the manganese dioxide anion (MnO2−) in an excited triplet state

Abstract

Photoelectron imaging, electron action spectroscopy and electronic structure calculations are used to probe the structure and dynamics of MnO₄⁻. Following excitation to the first bright absorption band of MnO₄⁻ (1¹T₂), photodetachment, via ground state electron loss, and photodissociation, to produce MnO₂⁻, are both observed to occur simultaneously. MnO₂⁻ is produced in an excited electronic state, identified as a triplet state, which indicates that the dissociation proceeds on singlet potential energy surfaces via spin conservation. Furthermore, electronic structure calculations indicate that both photodetachment and photodissociation are multiple photon processes that are mediated by the same 1¹T₂ excited state. Taken together this data indicates that photodissociation of MnO₄⁻ occurs via a statistical dissociation on the MnO₄⁻ ground state at visible wavelengths.