The Experimental Physical Chemistry and the Atomic, Molecular and Optical Physics Programs support William C. Stwalley of the Physics Department at the University of Connecticut in his continuing spectroscopic studies of diatomic molecules at long range. In this effort, Prof. Stwalley will collaborate with Prof. Phillip L. Gould, an expert in collisions of ultracold atoms. They will investigate the high-resolution photoassociative spectroscopy of ultracold alkali atoms using all optical multiple resonance spectroscopies. Emphasis will be on highly excited states of alkali metal diatomics (e.g., potassium or cesium dimers), but Stwalley and Gould will also attempt to observe photoassociation of atom-molecules such as Cs-H2. Molecules at long range are molecules in which the atoms are separated by very large distances, yet attractive forces are still strong enough to maintain a `molecular` nature. Such molecules are of great current interest, partly because new effects show up which will extend our knowledge of molecular potential curves, partly because of their relevance to the work in laser cooling and trapping and Bose-Einstein condensation. The studies that will be carried out in this new collaborative effort will greatly increase our understanding of chemical bonding by revealing the subtle forces that act to attract and `congeal` atoms separated by large internuclear distances. Successful completion of these studies will furnish highly detailed information on interatomic forces which, in turn, are of fundamental importance to our understanding of atomic collisions and the assembly of atoms into higher states of aggregation ranging from molecules, to clusters, and on to condensed phases.
