Absorption spectra of Mo atoms isolated in rare-gas matrices

The ultraviolet spectra of Mo isolated in Ar, Kr, and Xe matrices at 14°K have been correlated with the gas phase spectra. Contrary to the interpretations of the spectra of the P ← S transitions of a number of matrix isolated atoms, no crystal field effects leading to a breaking of the orbital degeneracy are required in order to obtain a satisfactory explanation of the spectra. The different matrices affect the spin-orbit coupling and configuration interaction of the Mo atom leading to changes in the triplet splittings of the y7P ← a7S transition. The diffusion of Mo atoms in an Ar matrix lead to the formation of polymers. No definitive assignment of bands to the dimer could be made.