MOLECULAR CLUSTERS - STRUCTURE AND DYNAMICS OF WEAKLY-BOUND SYSTEMS

Weakly bound atomic and molecular clusters can be viewed as finite-siz e ''pieces'' of the condensed phases of matter. From both the experime ntal and theoretical points of view, the finite size of these clusters is of great advantage in simplifying the system, permitting molecular level characterization of solvent effects on the solute spectroscopy and chemical reaction dynamics. In addition, the ability to vary the n umber of atoms or molecules in the cluster enables us to observe how i ts various structural and dynamical properties evolve with size, from those typical of isolated gas phase molecules toward the bulk limit. B y far the most detailed information has been obtained for binary compl exes, where the issues of interest are the determination of intermolec ular potential energy surfaces and understanding the vibrational dynam ics of these complexes. Considerable progress has also been made in th e characterization of higher-order complexes, which provide informatio n on many-body interactions and more realistically approximate solvate d systems. Since the breadth of this field precludes a complete review , we attempt here only to give some examples that illustrate the impor tant issues and convey some of the excitement.