Abstract
It is now possible to start with a simple model of a solid composed of atomic cores and itinerant valence electrons and compute the total energy for a given structural arrangement of atoms with enough precision to predict the existence of new solids and their properties. The application of the model based on the pseudopotential method is described with silicon chosen as a prototype material. With only information about the constituent atoms, the electronic, structural, vibrational, and even superconducting properties of solids can be calculated from first principles. The successful predictions of superconductivity in highly condensed hexagonal silicon and the existence of new high-pressure semiconductor phases are highlighted. A discussion is presented of the use of the method to discover new stable or metastable solids at high pressures.