Origin of the unusual stability of MnO4−

The attachment of an electron to manganese tetroxide cluster is found to lower its total energy by as much as 5 eV, thus putting MnO4 into the class of superhalogens. This result, predicted by first-principles calculations based on density functional theory and generalized gradient approximation, is verified experimentally by photodetachment spectroscopy. The combined theoretical and experimental studies not only allow a fundamental understanding of the origin of the unusual stability of MnO4− but also provide information on ground-state geometries, vibrational frequencies, and electronic structure of MnO4, MnO4−, and their isomers.