Infrared Photodissociation Spectroscopy of Ti+(CO2)2Ar and Ti+(CO2)n (n=3–7) Complexes

Abstract

Ti+(CO2)2Ar and Ti+(CO2)n (n=3–7) complexes are produced by laser vaporization in a pulsed supersonic expansion. The ion complexes of interest are each mass-selected in a time-of-flight spectrometer, and studied with infrared photodissociation spectroscopy. For each complex, a sharp band in the CO stretching frequency region is observed, which confirms the formation of the OTi+CO(CO2)n−1 oxide-carbonyl species. Small OTi+CO(CO2)n−1 complexes (n≤5) exhibit CO stretching and antisymmetric CO2 stretching vibrational bands that are blue-shifted from those of free CO and CO2. The experimental observations indicate that the coordination number of CO and CO2 molecules around TiO+ is five. Evidence is also observed for the presence of another electrostatic bonding Ti+(CO2)2 structural isomer for the Ti+(CO2)2Ar complex, which is characterized to have a bent OCO-Ti+-OCO structure stabilized by argon coordination.