The Chemical Structure, Dynamics and Mechanisms Program supports Dr. Charles E. Doubleday of Columbia University for the devleopment of non-statistical computational methods to better understand organic reaction mechanisms. This research will develop methods to compute the detailed sequence of atomic motions as starting materials are transformed into products (classical trajectories), using a combination of quantum mechanics and classical mechanics. Dr. Doubleday will examine reactions that are important in organic chemistry, and whose mechanisms of operation have remained elusive. These include unimolecular isomerizations and some bimolecular cycloadditions. A third type is enediyne cyclizations that occur in a powerful class of naturally occuring antibiotics. Dr. Doubleday will study quantum mechanical tunneling in these reactions, in addition to computing classical trajectories. In all projects, the goal is to understand the way in which energy flows from reactants to products. The deeper understanding gained will allow more precise control in designing molecules for specific applications. Â An important component of this project is the training of undergraduate students in scientific research. Since research is collaborative and students learn from each other, the work fosters group skills as well as individual achievement. In collaborations with colleagues at other institutions, Dr. Doubleday helps train graduate students in the use of trajectory methods. The principal investigator's classical trajectory program is available and is currently being used at other academic institutions. Benefits to society at large will emerge from a deeper understanding of the mechanisms of chemical reactions. In the enediyne project, the focus is on the active center of a class of powerful antibiotics, with the goal of understanding and control. As the principles uncovered by this research become incorporated into applied areas, potential benefits could include greater understanding and control over chemical processes important in atmospheric and life processes, and in human health generally.