Theory of Atomic and Molecular Clusters

The emergence and spectacularly rapid evolution of the field of atomic and molecular clusters are among the most exciting developments in the recent his- tory of natural sciences. The field of clusters expands into the traditional disci- plines of physics, chemistry, materials science, and biology, yet in many respects it forms a cognition areaofits own. The identifying attributes ofthis area reflect the specificity ofthe objects, subjects, problems, and issues it addresses, and the concepts, methodologies, techniques, and tools it utilizes. All these ultimately relate to and are defined by a single common characteristic - the finite size of the targeted systems. Theterm "finite" represents a broad rangeofsizes- from small (afew to a few tens of atoms and molecules) to large (thousands of atoms and molecules). This varietyof si~es and thesize-dependenceofthe propertieswould alone besufficient to make the cluster field a broad and challenging research area. The variety of elements one can use (and nature uses) to form clusters and the different types of interatomic interactions in clusters of different elements and materials only enhance the diversity and the richness of the field. To unravel, understand, and describe cluster properties one often has to in- voke complementaryconcepts and techniques, and, what is most challenging and stimulating, develop new ones. This book presents a "cross section" of theoreti- cal approaches and their applications in studies ofdifferent cluster systems. The last three articles provide a "glimpse" at experimental cluster research.