| Abstract: | Zeolites are unique in that they can play host to a large number of alkali-metal clusters of the type Mn+p hitherto unseen in any other system. When isolated, these clusters behave as color centers. The alkali ions reside in ionic sites within the cavities and so the nature of the cluster is very much a function of the zeolite host, the Si:Al ratio, and the method chosen to prepare the cluster. Since these centers are created within zeolite cages rather than as structural defects (as is the case with the alkali halides) high cluster concentrations can be achieved at which point the optical and magnetic properties of the zeolite change profoundly. We review experimental work in this area, as well as our own attempts to understand both the electronic and optical properties of these systems in terms of an electron solvation model. |
