Spectroscopy and Bonding of Group III Transition Metal Molecules

Transition metal containing molecules give rise to very challenging electronic spectra. This arises mainly from the involvement of the metal d electrons in the bonding. In this respect, compounds of group III metals represent prototypical systems, since they have the simplest opened shell electronic configuration: [core] (n-1)d$^{\\prime} ns^{2}$. A number of new and previously known Sc, Y and La containing molecules have been generated in a free jet molecular beam apparatus by chemical reactions in a laser vaporization source, and studied by laser induced fluorescence at a resolution of 120 MHz. Zero-field and Stark spectroscopy have been performed either on selected vibronie bands or on all observed visible bands, all of which are connected to the ground states. Rotational, fine and nuclear magnetic hypertine parameters as well as dipole moments have been derived using appropriate Hamiltonian matrix representations. The data will be compared with ab initio predictions and used to discuss aspect of the bonding.