During the past few years, there has been dramatic progress in theoretical and computational studies of large molecules and local- ized states in solids. Various semi-empirical and first-principles methods well known in quantum chemistry have been applied with considerable success to ever larger and more complex molecules, including some of biological importance, as well as to selected solid state problems involving localized electronic states. In- creasingly, solid state physicists are adopting a molecular point of view in attempting to understand the nature of electronic states associated...

During the past 20 years, solid state physics has become one of the major branches of physics. 1-2 Today over one-third of all scientific articles published in physics deal with solid state 3 topics. During the last two decades, there has also been ra id growth of scientific computation in a wide variety of fields. -5 The combination of solid state physics and comp tation may be termed computational solid state physics. This emerging field is distin guished from theoretical solid state physics only to the extent that electronic computers rather than slide rules or backs of envelopes are used...