9526658 GOLDFIELD This project, supported by the Theoretical and Computational Chemistry program will focus on the development of quantum chemical dynamical tools and the application to several chemical reactions. The primary focus of this development will be in the area of massively parallel computers. Currently, much progress is being made in the field of chemical dynamics. This progress is being fueled both by the development of new and clever computational methods and the incredible advances in computer power. Such progress means that for the first time, theoretical chemists can actually envision competing with their experimental colleagues in providing accurate accounts of important chemical phenomena. The aim of the research outlined in this proposal is to harness the power of massively parallel computing to enable chemists to apply rigorous theoretical methods to larger, more complex chemical systems. At the heart of chemistry lies the motion of atoms and molecules. The description of the motions of interacting atomic nuclei provides the most basic and fundamental understanding of chemical processes. An important goal of theoretical chemical physics is to describe chemical reactions from first principles alone. Because atoms are very small, their motions are often not adequately explained by ordinary Newtonian mechanics, instead, quantum mechanics is required. Although the quantum mechanical equations that apply to all of chemistry have been known for most of this century, only in the past several years has a complete, accurate theoretical description of a chemical reaction been given, and only for the simplest chemical process, the interaction of a hydrogen atom and a hydrogen molecules. There is a huge difference between knowing the form of an equation and having the methodological and computational tools which enable one to solve it. Chemical dynamicists for the most part have not yet exploited the huge potential of massive ly parallel computing. The research proposed here is to develop and implement a hierarchical parallel model for time-dependent quantum dynamics. The researchers expect that this model will allow them to obtain realistic descriptions of much larger and more complex chemical systems than is currently possible. They will apply this model to important and challenging problems including the two most important reactions in combustion chemistry. One very important property of this model, which has already been implemented, is its ability to handle easily and efficiently chemical systems having high overall angular momentum. Many theoretical efforts concentrate on the computationally more tractable systems with zero total angular momentum; such states are rarely found in nature however. There are often both quantitative and qualitative differences between high and low angular momentum states. Therefore, in order to compare theoretical calculations with experiments it is often necessary to obtain an accurate description of nonzero angular momentum states.
