In this project in the Physical Chemistry Program of the Chemistry Division, Prof. H. Strauss of the University of California will investigate the vibration-rotation spectra of small molecules in order to study the dynamical interactions in the condensed phase. In this work the methods of infrared and Raman spectroscopy, neutron spectrscopy, time-dependent vibrational excitation, and theoretical analysis will be used to explore the dynamics of a number of liquid and solid systems. The emphasis is on chemical systems that illustrate important general methods or elucidate important intermolecular interactions. Infrared "holeburning" is used to study the ability of infrared radiation to cause changes in the molecular conformation and structure in solids at low temperature. Raman spectral data of hydrogen gas dissolved in water or ice will be combined with theoretical calculations to determine the nature of the interactions in these systems. The nearly free rotation of deuterated ammonium ions embedded in ammonium salts will be studied to ascertain the cause of observed different rate processes of reactions and to determine the effect of the inhomogeneous environment on them. The iodine-benzene complex interaction will be investigated by Raman spectroscopy in order to understand the dynamics of the ground and excited states. %%% These investigations serve to improve our understanding of molecular interactions in the condensed phase. These interactions have a profound effect on the reaction dynamics and kinetics in liquid and solid systems. The work on molecular hydrogen dissolved in ice will provide important data on the behavior of a quantum mechanical rotator embedded in a classical bath and will assist in the development of theoretical models for this process. Such knowledge will be of use in understanding the properties of cold planets and moons which are believed to contain the hydrogen/ice system in their surface layers.
