Knowledge Bank

A beam of large helium clusters, made each of approximately $104$ atoms, is used to ""matrix isolate"" high spin alkali dimers and trimers. The high spin triplet and quartet states formed on the clusters survive preferentially over their singlet and doublet counterparts. The large energy liberted by the low spin species upon formation will destroy a larger fraction of the host clusters. Total and dispersed fluorescence studies have allowed the recording of several previously unobserved alkali dimer triplet to triplet transitions and the first quartet to quartet transition of the Na trimker. The results indicate that the Hartree-Fock plus damped Dispersion interatomic potential model (HFD) accurately describes the interactions in the lowest alkali triplet states and provide information on the (strong) presence of three body forces in the interaction of three spin-polarized alkali atoms.