Abstract

The YS molecule has been produced in a free jet molecular beam apparatus by laser vaporization of yttrium metal in the presence of He carrier gas doped with 1–2% of CS₂, and its visible spectrum has been studied by laser induced fluorescence. The B²Σ⁺−X²Σ⁺ (0,0) and A²Π−X²Σ⁺(0,0) bands have been studied at sub-Doppler resolution, and rotational, fine, and hyperfine parameters have been derived. Both hands are complicated by local perturbations, which also have been analyzed in detail. The first rotational lines of the B²Σ⁺−X²Σ⁺ (0,0) band have been used to determine the permanent dipole moment of both the X and B states. Several other bands not belonging to the B−X or the A−X systems and that to our knowledge have never been reported before have also been observed and are currently the subject of intensive studies. The data will be compared with the predictions of ab initio calculations and the ligand field model and will be used to discuss aspects of the bonding.

© 1992 Optical Society of America