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

TL;DR

This study performs a comprehensive, mass-independent spectroscopic analysis of various titanium monoxide isotopologues, revealing effects beyond the Born-Oppenheimer approximation and enabling precise predictions for astronomical detection.

Contribution

It introduces the first mass-independent analysis of TiO isotopologues, combining experimental data with quantum calculations to understand electronic structure and isotopic effects.

Findings

Revealed deviations from the Born-Oppenheimer approximation in TiO

Predicted rotational transition frequencies of $^{44}$TiO with sub-MHz accuracy

Provided spectroscopic parameters for rare isotopologues

Abstract

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.