This award will support a two-year cooperative research project in chemical dynamics between two groups at the University of Chicago and two groups at the Institute for Molecular Science, Okazaki. Professors Graham R. Fleming and Jeffrey A. Cina will work with Professors Keitaro Yoshihara and Iwao Ohmine and their associates on studies of chemical dynamics in solution. The studies combine ultrafast spectroscopy with theory and simulation and are aimed at building up a detailed understanding of how solvents influence the rate and outcome of chemical reactions. Such reactions are often modeled as occuring on simple one- dimensional potential surfaces. The other degrees of freedom - in- tramolecular vibrations are either modeled statistically or simply ignored. The roles of the solvent in modifying the potential surface and in influencing motion along it are generally regarded as distinct ("static" and "dynamic"). The development of a more realistic description of simple chemical processes such as photochemical isomerization is hampered by ignorance of vibrational dynamics, of the true potential surface, and of the various time scales of the solvent response. The goal of this collaborative project is to combine the experimental and theoretical strengths of the groups at the U.S. and Japanese institutions to specifically address these questions. The experimental programs at both Chicago and Okazaki represent the state of the art. They are complementary in several ways. The groups at Chicago have developed fluorescence spectroscopy further than the Okazaki groups, while the Okazaki groups have developed unique femtosecond studies of clusters. The FSCAR and Raman spectroscopies require different set-ups and will give complementary information. The use of very large scale computing to combine electronic structure and dynamical modeling is well developed at Okazaki and the enormous computing power available there will allow calculations that could not be contemplated in the United States. It will be of great value to see how such calculations influence the thinking of experimentalists. Both the U.S. and the Japanese groups possess great strength in analytical studies of condensed phase dynamics and again, the exposure to the large computer calculations in Japan will be most valuable to the American groups. Finally, as an important part of the project, two U.S. graduate students will participate in the study, spending time each year in the Japanese laborator- ies.
