Photodissociation of permanganate (MnO 4 - ) produces the manganese dioxide anion (MnO 2 - ) in an excited triplet state.

Photoelectron imaging, electron action spectroscopy and electronic structure calculations are used to probe the structure and dynamics of MnO 4 - . Following excitation to the first bright absorption band of MnO 4 - (1 1 T 2 ), photodetachment, via ground state electron loss, and photodissociation, to produce MnO 2 - , are both observed to occur simultaneously. MnO 2 - 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 1 1 T 2 excited state. Taken together this data indicates that photodissociation of MnO 4 - occurs via a statistical dissociation on the MnO 4 - ground state at visible wavelengths.