This award will facilitate collaboration between Professor Robert W. Field, Department of Chemistry, Massachusetts Institute of Technology, and Professor Soji Tsuchiya, University of Tokyo, Japan, and members of their respective research groups. The scientists will utilize experimental and theoretical approaches to obtain information about unimolecular (single molecule) chemical reactions from rotation- vibration spectra of highly excited small polyatomic molecules (molecules containing more than two atoms) such as hydrogen cyanide, sulfur dioxide, and acetylene. Such spectra are intrinsically uninterpretable in the traditional spectroscopic sense. This collaboration will explore new experimental ways to generate large quantities of high-quality, interpretable spectra as well as new, statistically based ways to obtain information from these spectra. If successful, the effort will permit, for the first time, the extraction of detailed information about certain chemical processes, such as unimolecular isomerization, from high resolution spectra of highly energized molecules. Knowledge of the factors controlling intramolecular energy flow will lead to opportunities to diagnose, design, and effect excitations localized in specific parts of a molecule. The purpose of this project is to gain a fundamental understanding of intramolecular vibrational energy redistribution in isolated, small polyatomic molecules that are energized with chemically interesting amounts of internal rotation-vibration excitation. These molecules are simple enough that they can be examined in detail by state-of- the-art experimental and supercomputer-based theoretical techniques. For example, the isomerization of HCN to HNC following excitation of the molecule may be studied in this way. Complementary experimental and theoretical approaches in the two research groups will be utilized. As a significant part of this project, graduate students in Professor Field's group will make approximately one-month working visits to the University of Tokyo laboratory, and associates of Professor Tsuchiya will make similar visits to MIT.
