OPTICAL-PROPERTIES OF A CHROMOPHORE EMBEDDED IN A RARE-GAS CLUSTER - CLUSTER-SIZE DEPENDENCE AND THE APPROACH TO BULK PROPERTIES

One of the most intriguing aspects of the behavior of small clusters i s the extent to which their physical and chemical properties depend se nsitively on the size of the clusters. But for clusters that are ''lar ge enough,'' surely their properties must approach those of the corres ponding bulk systems. The property of special interest in the present work is the shift in the electronic absorption of a chromophore (benze ne) deriving from interaction with nonpolar solvent atoms (Ar), a shif t that can be calculated using a microscopic formalism described in th is and in the preceding paper which is equally well suited to the stud y of cluster and condensed phase environments. We are able to identify the evolution of the collective character of the dielectric response of the solvent atoms as being the key feature of the optical propertie s of these clusters that determines the degree to which their behavior is bulklike. Furthermore, we can associate specific spectral features with particular classes of cluster geometries, and in doing so we der ive support for our previous speculations concerning the evidence for the contribution of metastable, nonwetting cluster structures to the e xperimental spectra.