ASSIGNMENT OF IMPURITY STATES IN XENON-DOPED ARGON CLUSTERS - PERTURBED ATOMIC RYDBERG STATES VERSUS IMPURITY WANNIER EXCITONS AND THE IMPLICATIONS FOR DOPED RARE-GAS SOLIDS

Electronic excitations of XeMArN clusters are studied using fluorescen ce excitation spectroscopy in the energy range of the electronic excit ations of pure Xe. The composition of the clusters is changed between XeArN and pure Xe-M by varying the concentration of Xe gas in a coexpa nsion between 0.01% and 15%. The evolution of the absorption bands of XeArN clusters is investigated as a function of cluster size (N = 10-5 000). The character of the excitations is discussed in view of two the oretical models, namely perturbed atomic states and Wannier impurity e xcitons. The experimental results clearly favour the model of perturbe d atomic states which should also be a suitable description for excita tions in Xe-doped solid Ar.