Quantum Mechanical Structure and Dynamics of Complex Systems

Donald G. Truhlar of the University of Minnesota-Twin Cities is supported by the Theoretical and Computational Chemistry program to perform research on the development and implementation of new methods for simulating complex, reactive dynamical systems in chemistry. Research is underway in the calculation of rate constants for reactions catalyzed by enzymes and branching ratios of photochemical reactions. Method developments include the use of Feynman path integrals for thermochemical reactions, vibrational configuration interaction for converged quantum mechanical rate constants, and improved density functionals for transition metals and main-group barrier heights. A common theme of the research is the incorporation of quantum mechanical effects in complex systems. Specific applications include the temperature dependence of kinetic isotope effects in enzymatic reactions, a semiclassical trajectory method for dynamics on excited potential energy surfaces, path integral methods for dynamics, and variation-perturbation theory for complex systems. The PI is active in the creation of new educational and interdisciplinary infrastructures, and in organizing national workshops and symposia. This work is having a broader impact in the technological importance of the research areas to health, advanced materials, industrial competitiveness and defense. Software developed by this project will be made freely available in portable, well-documented form on the PI's website.