UV electronic spectra and structure of thallium-rare gas complexes

Several higher lying excited electronic states of Tl-Rg (Rg = Ar, Kr, Xe) van der Waals complexes have been investigated. Analysis of the transitions arising from the 6d(2)D <----> 6p P-2 transition of Tl atoms provides information about their ground state binding energies, and leads to the conclusion that the potentials of the lowest excited B-2 Sigma(+) states of the complexes exhibit a substantial (100-150 cm(-1)) potential barrier.