Predissociation spectra in the 2.6-3.3 μm region were observed for protonated chlorine nitrate and protonated nitric acid as well as some of their isotopomers (HXNO3+, X = H, D, 35Cl, 37Cl). Two protonated isomers of both ClONO2 and HNO3 were identified from the vibrational spectra. The lowest energy isomer was the ion-molecule complex NO2+(HOX) formed by protonation of the XO group. The second isomer was the metastable species (HO)(XO)NO+ formed by protonation of a terminal oxygen; this isomer was generated only under hotter ionizing conditions. The vibrational band centers of these isomers agreed well with ab initio predictions. Vibrational excitation of the HXNO3+ species studied here led solely to NO2+ + HOX products. Predissociation of the covalently bound metastable isomers (HO)(XO)NO+ to these products required an IR-induced rearrangement involving simultaneous 1,3 hydrogen shift and charge transfer. The results presented here were consistent with predictions of ab initio calculations and previous mass spectrometric and kinetic studies.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry