SPECTROSCOPIC PROBES OF METAL CLUSTERS PRODUCED IN SUPERSONIC EXPANSIONS
HOPKINS, JOHN BRIAN
Doctor of Philosophy
The cooling capabilities of supersonic expansions provide a powerful tool for investigating polyatomic molecules. Complex, optical spectra of room temperature molecules can be enormously simplified by the supersonic jet method. In recent years, this technique has provided a wealth of new information concerning the structure and dynamics of a wide class of molecules. A new technique has been developed to produce interesting species which do not readily exist under normal laboratory conditions. In particular, a pulsed laser is used to vaporize bulk metal material in conjunction with a supersonic expansion. The latter cools the hot metal vapor where clustering of metal atoms occur. In this fashion, clusters of refractory metals such as Ni(,x), Fe(,x), Mo(,x) and W(,x) have been readily produced. Spectral investigations using mass selective photoionization of Cu(,2), Ag(,2), Mo(,2) and Cu(,3) have been performed. The resulting spectra have been used to characterize the internal energy of jet-produced metal clusters. In addition, the spectra have been examined for new information regarding the electronic structure of these molecules.