Peter Debye Award In Physical Chemistry

Sponsored by E. I. du Pont de Nemours & Co..

Richard J. Saykally, Class of 1932 Professor of Chemistry at the University of California, Berkeley, "has been a participant from the ground up in the development of key spectroscopic techniques to characterize water and other liquids, from small clusters to the bulk, including infrared laser spectroscopy of clusters, far-infrared laser vibration-rotation-tunneling spectroscopy of clusters, cavity ringdown laser absorption spectroscopy, X-ray spectroscopy of liquid surfaces, and ultraviolet femtosecond second harmonic generation spectroscopy of ions at the liquid water surface, to name but a few of the most prominent," writes a colleague and former graduate student. "He is truly one of the experimentalists who have maintained spectroscopy as a vital enterprise at the most fundamental level."

Another colleague writes, "Over the last 20 years, Saykally has made the most original contributions to the field of high-resolution spectroscopy. In my view, he is now the world leader in this central field of molecular science. He has achieved this lead through pioneering studies of a remarkable variety of problems. from the first measurements of spectra for some small molecular ions, the determination of the structure of carbon clusters and radicals, and to the detailed study of the structure and dynamics of water clusters."

Saykally performed the first detailed study of small water clusters, including the trimer through hexamer. This work spurred modelers and theorists to develop improved water potentials, beginning with the simplest cluster, the water dimer. He also had a hand in the force field development, which was subsequently extended and made even more accurate by others. His spectroscopic studies provide the key benchmarks for theoretical chemists who wish to improve our understanding of water by producing size-scaleable force fields.

The most recent advances from the Saykally laboratory are in the study of surfaces of aqueous electrolytes by femtosecond UV second harmonic generation spectroscopy (SHG). By exploiting the strong charge-transfer-to-solvent bands of aqueous anions, resonantly enhanced SHG measurements have clearly demonstrated that certain inorganic anions such as azide or thiocyanate are not only present at the aqueous liquid-vapor interface, but can actually exist there in much higher concentrations than in the bulk. The effect has been verified for several species. The work allows detailed tests of theoretical models, particularly of Gibbs free energies of adsorption, and provides compelling evidence that even the hydronium ion itself may be enriched at surfaces.

His other recent work involves applying X-ray methods to interfaces and solvation processes. By applying near-edge and extended X-ray absorption methods to study liquid microjets, Saykally has resolved the controversy on the continuous distribution of hydrogen bond energies in liquid water, discovered new conformations of amino acids and peptides as a function of pH, and explained in new detail how salts influence water structure.

Saykally holds a Ph.D. in chemistry from the University of Wisconsin, Madison (1977). He was an NRC Postdoctoral Fellow at the National Institute of Standards & Technology's, Boulder facility (1977–79) before he took his first faculty position at UC Berkeley, where he has been ever since. He is the recipient of nearly 60 awards and honors, including the ACS Irving Langmuir Award in Chemical Physics (2000) and the Centenary Medal of the Royal Society of Chemistry (2001).

Saykally will present the award address before the Division of Physical Chemistry.