Energetics and dynamics of molecular clusters

We address some of the unique and basic features of molecular clusters, which involve (i) surface, interior, and site-selective energetics and dynamics, and (ii) the size dependence of the energetic, spectroscopic, electromagnetic, and dynamic attributes of large finite systems. Cluster-size equations provide a unified (but not universal) description of the "transition" of different attributes of clusters to those of the macroscopic bulk material. We explored fundamental issues, e.g., the physical origins of cluster-size effects, which originate either from cluster packing or from excluded volume contributions, and discussed some applications for the quantification of the size dependence of site-specific ionization potentials, extravalence and intravalence electronic spectroscopy, collective vibrational excitations, and dynamic effects. The quantification of dynamic cluster-size effects for energy acquisition in high-energy cluster-wall collisions opens avenues for the exploration of cluster-impact thermal femtosecond chemistry.