The Rotationally Resolved Infrared Spectrum of TiO and Its Isotopologues

Abstract In this study, we present the ro-vibrationally resolved gas-phase spectrum of the diatomic molecule TiO around 1000 cm-1. Molecules were produced in a laser ablation source by vaporizing a pure titanium sample in the atmosphere of gaseous nitrous oxide. Adiabatically expanded gas, containing TiO, formed a supersonic jet and was probed perpendicularly to its propagation by infrared radiation from quantum cascade lasers. Fundamental bands of 46–50TiO and vibrational hotbands of 48TiO are identified and analyzed. In a mass-independent fitting procedure combining the new infrared data with pure rotational and electronic transitions from the literature, a Dunham-like parameterization is obtained. From the present data set, the multi-isotopic analysis allows to determine the spin-rotation coupling constant γ and the Born-Oppenheimer correction coefficient Δ U 10 Ti for the first time. The parameter set enables to calculate the Born-Oppenheimer correction coefficients Δ U 02 Ti and Δ U 02 O . In addition, the vibrational transition moments for the observed vibrational transitions are reported.