MOLECULAR BEAM STUDIES OF REACTIVE SPECIES (COPPER, RADICALS, METAL CLUSTERS)
POWERS, DAVID EDWARD
Doctor of Philosophy
Techniques are described for studying reactive species, in particular radicals and metal clusters but generalizable to most molecules which can be made by photolytical processes from stable precursors. Methods for radical formation in a supersonic molecular beam by laser photolysis are described. The B(<---)X transition in methoxy radical has been vibrationally and rotationally resolved and is discussed. Electronic, vibrational and rotational cooling of the radical is shown to be substantial with this technique. Laser vaporization combined with molecular beam techniques are described as they can be applied to metal cluster studies. Ionization potentials have been bracketed for clusters of copper up to 28 atoms. The potentials approach that of the bulk metal as the cluster size increases but for Cu(,28), there still remains a significant difference from the work function of the bulk metal. Copper dimer electronic spectra in the visible and ultraviolet regions have been studied and several new band systems have been seen. An observed long ground state progression is believed to be due to a very tightly bound excited state of the dimer. Two interacting states are observed and the resulting perturbed levels are modeled with a simple pair wise interation. Other fragmentary systems and previously seen visible systems are also discussed.