A major theme of current research in Professor Klemperer's group is geometric and electronic structure of van der Waals molecules and weakly bound complexes. We can determine the nature of weak bonding with the same detail and precision as exists for the strong chemical bonds. The experimental studies utilize molecular beam techniques for producing spectroscopic data in low effective temperature (5K) supersonic jets, a virtually new state of matter, the frozen gas. Analysis of the spectra involves modeling of internal dynamics in non-rigid molecular systems and testing theoretical potential energy functions and electronic charge distributions. Of the many types of weak bonds that frequently occur, hydrogen bonding is exceptional. We are concerned with proton mobility as well as the location of atoms.
A related topic is the study of highly excited vibrational states of simple molecules. The behavior of polyatomic molecules at energies in which many states exist is of continuing current concern. Thus the basis for such fundamental processes as energy flow/localization, isomerization paths, photodissociation time scales may be determined. The dynamical behavior of systems at high energy is studied spectroscopically. The high spectral resolution readily available today permits detailed probing of a variety of systems. The more complex the spectrum, the richer is the phenomena, but the more difficult is its characterization. There are many opportunities for the development of novel experiments and their theoretical interpretations.
A major portion of the interstellar medium is the cold (10K) low density (10e-16 atm) region between stars. Chemistries of the interstellar medium are novel in that they occur in general, at these extreme low temperatures and densities, with relatively high efficiencies. The ever increasing astronomical observations, primarily radio astronomy, provide a broad source of unique information against which tests of our understanding of fundamental chemistry and molecular physics may be made. Our research involves primarily modeling the kinetic behavior of this fascinating region.