Walter Kohn, Nobel Laureate, University of California Santa Barbara, presented the 2012 Green Family Lectures at the Institute for Pure and Applied Mathematics in May 2012. Research Lecture: Electronic Structure of Matter: Wave Functions and Density Functionals Wednesday, May 30, 2012 CNSI Auditorium Abstract: In 1926 Schrödinger published his famous equation which revolutionized all of chemistry and a great deal of physics. In principle, (apart from relativistic effects), it described completely the electronic structure of matter, including atoms, molecules, solids, liquids, and plasmas. However, in practice, unless symmetries radically simplified matters, calculations with “chemical accuracy” were usually limited to systems of ten to twenty atoms. Beginning in 1964 a new viewpoint, called Density Functional Theory, was developed, which is based on the probability density distribution of electrons in the system in question. Apart from providing additional insights into electronic structure, it has also allowed extensions to much larger systems, up to 500 to 1000 atoms. It has found a great many practical applications in physics and chemistry, for example, to defects in solids, drug design, and biological molecules. In this talk I will explain the basic ideas of Density Functional Theory, compare its strengths and weaknesses with those of the more traditional wave function approach, and describe some applications. Additional Materials: View Powerpoint Presentation Density Functional Theory (Presented by Ann Mattsson) Quantum Mechanical Methods for Drug Design (Provided by Dr. Kohn as supplemental material) Nearsightedness of Electronic Matter (Provided by Dr. Kohn as supplemental material)