Predicting molecular structure and energy and explaining the nature of bonding are central objectives in quantum chemistry. In this volume, which is based on a 1990 workshop held at the Ohio Supercomputer Centre, specialists on the density functional (DF) method and its chemical applications demonstrated how their work contributed to these goals and how it has become an advanced method of computational chemistry. Density functional theory has emerged as an alternative to the traditional ab initio and semi-empirical approaches of quantum chemistry for studying the ground state properties of molecular systems. Advantages of the method are its accuracy and efficiency, which makes it suitable for the realistic study of large molecular systems. The book describes organic, inorganic, metallic and semiconductor systems consisting of elements throughout the periodic table. For these reasons, density functional methodology is used increasingly in pharmaceutical, agrochemical and biotechnology research; materials and polymer science; catalysis, surface and solid state research; and electrochemistry and micro-electronics.