This grant from the Theoretical and Computational Chemistry Program supports studies of the electronic structure of neutral and charged molecules. In particular, negative ion clusters, the interaction of anions with inert gas atoms, the trapping of electrons by clusters of polar molecules, the interactions of small molecules with aluminum clusters, and the potential energy surfaces of excited electronic states of ozone and of substituted ethylenes will all be examined. These studies will elucidate the microscopic dynamics of many chemical processes of current interest.