Measuring, Modeling, and Computing Resonances among Excited Vibrational States of Polyatomic Molecules
By William F. Polik, Department of Chemistry, Hope College
Abstract: Resonances play a fundamental role in the mechanics and dynamics of classical and quantum systems. In chemistry, for example, resonances are responsible for bonding among atoms, molecular spectroscopy, and energy flow within molecules. Understanding vibrational resonances is necessary to interpret the spectra of excited vibrational states, which in turn provide experimental insight into molecular potential energy surfaces and the dynamics of energy flow on those surfaces. Experimental approaches for measuring excited vibrational states will be described, with an emphasis on the method of Pure Vibrational Spectroscopy which allows the observation of vibrational states unobscured by rotational congestion. Spectroscopic evidence for vibrational resonances will be presented for several molecules. The implication of these resonances for determining potential energy surface parameters and the extent of energy flow will be discussed. A practical approach for a priori prediction of the presence and effect of vibrational resonances will also be presented and compared to experiment.
Biographical Sketch: Dr. William Polik graduated from Dartmouth College in 1982 and received his Ph.D. in physical chemistry from UC Berkeley in 1988. He then joined the faculty at Hope College, where he is the Edward and Elizabeth Hofma Professor of Chemistry and Chair of the Chemistry Department. He has received numerous research and teaching awards, including a NSF Presidential Young Investigator award, being named an AAAS and an ACS Fellow, and receiving the Hope College Provost's Award for Teaching Excellence. He has involved 70 students in his research program at Hope College, of whom 28 are co-authors on publications. Dr. Polik has been very active in curriculum development and most recently co-developed the WebMO web-based interface for computational chemistry, which is in use at over 2,000 academic and research institutions worldwide. Dr. Polik has served on the ACS DivCHED physical chemistry examination development committee, chaired the Beckman Scholar Program Executive Committee, and chaired of the ACS Committee on Professional Training during its past revision of the Guidelines for Approval of Undergraduate Chemistry Programs.