High Resolution Spectroscopy With Molecular Beams and Tunable Lasers

High resolution Doppler-free laser techniques are used in beam experiments to improvethe spectroscopic description of complex diatomic molecules. The case of TiO isconsidered here for its implication in reaction dynamics studies and its interest inAstrophysics. Two absorption bands in the visible have been analyzed: B 3 Π − X 3   Δ ( 1 − 0 )andc 1 Φ − a 1   Δ ( 0 − 0 ) . Owing to accurate wavenumber measurements,it has been possible to extend the analysis to high rotational quantum numbersand to carry out detailed spectroscopic calculations. They show that a careful revisitingof the TiO electronic structure is necessary.