Mass-independent analysis of the stable isotopologues of gas-phase titanium monoxide -- TiO

More than 130 pure rotational transitions of \(^{46}\)TiO, \(^{47}\)TiO, \(^{48}\)TiO, \(^{49}\)TiO, \(^{50}\)TiO, and \(^{48}\)Ti\(^{18}\)O are recorded using a high-resolution mm-wave supersonic jet spectrometer in combination with a laser ablation source. For the first time a mass-independent Dunham-like analysis is performed encompassing rare titanium monoxide isotopologues, and are compared to results from high-accuracy quantum-chemical calculations. The obtained parametrization reveals for titanium monoxide effects due to deviations from the Born-Oppenheimer approximation. Additionally, the dominant titanium properties enable an insight into the electronic structure of TiO by analyzing its hyperfine interactions. Further, based on the mass-independent analysis, the frequency positions of the pure rotational transitions of the short lived rare isotopologue \(^{44}\)TiO are predicted with high accuracy, i.e., on a sub-MHz uncertainty level. This allows for dedicated radio-astronomical searches of this species in core-collapse environments of supernovae.