2008ApJ...676.1367B

The rotational spectrum of titanium dioxide (TiO₂) has been detected by laser-ablation molecular beam Fourier transform microwave spectroscopy. Thirteen b-type rotational transitions up to J=9 and K_a=4 were measured for the most abundant isotopic species ⁴⁸TiO₂ in the frequency range 7-42 GHz with accuracies of 1-10 kHz, allowing for the precise determination of rotational and centrifugal distortion parameters. In addition, eight and six rotational transitions of the rare isotopic species ⁴⁶TiO₂ and ⁵⁰TiO₂, respectively, have been recorded in the same frequency range. From the derived spectroscopic parameters, rest frequencies of TiO₂ can now be calculated to better than 1 km/s in equivalent radial velocity up to fairly high J and K_a at millimeter wavelengths, enabling radioastronomical searches for this stable, highly polar transition metal dioxide in space. Preliminary results of two searches for TiO₂ in space are presented.