THE ELECTRONIC STATES OF METAL-AMMONIA CLUSTERS AND SOLUTION

A new model e--NH3 pseudopotential parameterized to ab initio quantum chemistry calculations on small lithium ammonia clusters is studied in a variety of environments. Results for Li(NH3)n(n = 1,4) presented in a previous work are reviewed. Large clusters (n = 16, 32, 64, 128) are then studied. The valence electron is found to exist in a surface state far from the lithium ion which is localized at the center of mass of the cluster. Bulk properties of both a single excess electron and the lithium atom in solution are also reported. The solvation energy and spectrum of the excess electron are found to agree well with experiment though the spectrum is somewhat blue shifted. The valence electron of the lithium atom is found to dissociate spontaneously, a property which has not been reproduced in early work. Some preliminary results on the singlet state of two excess electrons in ammonia are presented