Steven D. Schwartz of Yeshiva University is supported by an award from the Theoretical and Computational Chemistry program to carry out research on the development of mixed quantum/semiclassical approaches to chemistry in complex systems. Schwartz is also developing an approximate quantum mechanical transition path sampling method, an approach based on the melding of classical transition path sampling techniques with the semiclassical centroid molecular dynamics technique. <br/><br/>The newly developed methods are being applied to several systems including dihydrofolate reductase protein, common in organisms which live in very high temperature environments. The work is having a broad impact on our understanding of reaction dynamics in complex systems, particularly those in biology.