Metastable Peaks in the Mass Spectra of N2O and NO2

Metastable states in N2O+ and NO2+ have been observed, the product ion of the metastable dissociation being NO+ in each case. In N2O+ (m), with a half-life of ≤0.2×10−6 sec, the total kinetic energy given to the fragments NO+ and N was found to be 1.05±0.05 eV. In NO2+ (m) two processes are found, one of half-life 0.7±0.1×10−6 sec which leads to a total kinetic-energy release of 1.12±0.10 eV, and a second of half-life 2.5±0.5×10−6 sec which leads to a total kinetic-energy release of 0.51±0.10 eV. The effect of pressure on peak height shows the metastable peak from N2O+ to possess a unimolecular component, which, under proper conditions of operation, can be made to predominate over a normally intense collision-induced dissociation peak. The metastable peaks from NO2+ both arise from unimolecular dissociation processes.