title: Fluorescence and metastability of N2O2+: theory and experiment.
abstract: State-selective mass spectrometry has revealed one conclusive and another probable metastable state of the N2O2+ dication, assigned respectively as 1 3Pi at 38.5 eV and 2 3Pi at 42.5 eV. Photon coincidence experiments confirm that dissociation of 1 3Pi is preceded by a fluorescent transition to X 3Sigma- and also indicate that an identical mechanism occurs for 2 3Pi. Highly correlated MRCI calculations are performed at a range of N2O2+ geometries, from which both N-N and N-O bond stretching curves are generated. Substantial barriers along both coordinates are observed for 1 3Pi and 2 3Pi, although the increasing density of states at higher energy may allow spin-orbit or vibronic predissociation for 2 3Pi. Fragment emissions derived from N2O+ and N2O2+ are analyzed with the aid of glass filters, from which NO (X 2Pi<--A 2Sigma+) and vibrationally excited N2+ (X 2Sigmag+<--B 2Sigmau+) transitions are deduced.
authors.affiliation: Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom. stuart.taylor@chem.ox.ac.uk
authors.forename: S
authors.initials: S
authors.lastname: Taylor
authors.forename: J H D
authors.initials: JH
authors.lastname: Eland
authors.forename: M
authors.initials: M
authors.lastname: Hochlaf