SHAVITT,ISAIAH

The scientific achievements of Isaiah Shavitt are reviewed. These star t with the Boys and Shavitt 1956 publications on the calculation of vi rial coefficients and the H-3 potential surface, two of the first appl ications of the newly available computer to chemistry. The list of lan dmark achievements also includes the Gaussian transform method for cal culating multicenter integrals of Slater-type orbitals and the first p roposal of contracted Gaussians as basis orbitals. Shortly before Shav itt left Israel in 1967, he began a long string of seminal contributio ns to the method of configuration interaction, including schemes for a utomatic generation of lists of configuration state functions and for selecting the configurations with the largest contributions to the tot al energy. With these methods, he carried out extensive (for the time) configuration interaction calculations using Slater orbitals and mini mum basis sets. In subsequent years at Battelle and Ohio State Univers ity, with the help of a notable group of postdoctoral fellows and grad uate students, Shavitt produced, with ever-increasing accuracy, many c arefully done and detailed molecular studies, including C6H6, CH2, and the H2O vibrational surface. Even more influential were his contribut ions to developing new techniques, particularly obtaining eigenvalues of large matrices and developing the graphical unitary group approach to configuration interaction and related correlation energy methods. T he ideas originated by Shavitt throughout his career influence deeply the way we do quantum chemistry to this day. In all his work, Shavitt was noted for the thorough and careful computational procedures he ins isted upon before a paper was considered complete. Isaiah Shavitt was a professor at the Technion from 1962 to 1967. In 1967 he moved to Col umbus, Ohio, to take a senior research position at Battelle Memorial I nstitute. The following year he added a part-time faculty position at the Department of Chemistry at Ohio State University. In 1981, he with drew from Battelle and became a full-time faculty member at Ohio State University. In 1994 he retired from this position and is continuing p art-time in emeritus status.