In this study supported by a Career Advancement Award from the Theoretical and Computational Chemistry program of the Chemistry Division models are being developed to characterize the electronic structure and spectra of nanoscale size semiconductor crystallites such as cadmium selinide. Special emphasis is being placed on determining the role of shapes, sizes, and surface characteristics in influencing the properties of these crystallites. Extensive use is being made of computer codes developed for these studies. %%% Tiny crystals of semiconducting materials such as cadmium selenide are very important in the development of new electronic devices. In this study theoretical and computational methods are being developed and utilized to characterize the electronic and optical properties of these crystals.