9403780 Hase Wayne State Univ. This project in the theory of chemical dynamics is supported by the NSF Theoretical and Computational Chemistry Program. The investigator extends his broad, ongoing study of transition state theory, classical trajectory calculations, SN2 reactions, RRKM theory of unimolecular reactions, solvent effects, dynamics of gas-surface interactions, and further development and application of the VENUS computer program. This project emphasizes direct dynamics (thereby avoiding the problem of fitting the global potential energy surface) and the treatment of quantum mechanical zero point energy effects in a classical mechanical formalism. VENUS is a computer program, used by theoretical chemists at various institutions, to predict the rates of chemical reactions in gases, liquids, and at gas-surface interfaces using detailed knowledge of the intermolecular forces for the specific molecules in the chemical system. The underlying theoretical principles and computational methods have been continuously developed over many years by numerous scientists with major contributions coming from the principle investigator's own research group. This project attempts to compute the trajectories of atoms in the course of a chemical reaction without prior knowledge of the potential energy surface (a mathematical function expressing the energy of any given geometical arrangement of atoms). Instead, the instantaneous energy, and the associated interatomic forces, are recomputed at each step along the reaction path. Improved computational methods need to be developed before such computations become generally practical.
