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Coherent Broadband Microwave Spectroscopy

APS March Meeting 2010

Focus Session: New Trends in Spectroscopy II


Wednesday, March 17, 2010 - 8:00am

Oregon Convention Center, Portland, OR


Brooks H. Pate

William R. Kenan, Jr. Professor of Chemistry

Director of Astrochemistry in Charlottesville

University of Virginia, Charlottesville, VA 22904

Tel: (434) 924-7219; Fax: (434) 924-3710


Research Page:




Recent advances in high-speed digital electronics have made it possible to develop a new type of Fourier transform microwave spectrometer that provides true broadband detection. These spectrometer use linear sweep chirped pulses for polarization of the molecular sample. The subsequent broadband free induction decay is digitized with a high-speed (50 Gs/s) 8-bit digitizer and the frequency domain spectrum is obtained by fast Fourier transformation. Spectrometer designs covering the 2-8 GHz, 6.5-18.5 GHz, and 25-40 GHz frequency bands will be presented. The spectrometer design is applicable to both pulsed jet molecular beam sources and to low-pressure gas samples at room-temperature. Measurement approaches to enhance the spectrometer sensitivity and reduce sample consumption will be presented. The technological advances in core spectrometer components expected over the next few years will also be described. Applications of this measurement technique to problems in molecular structure determination, chemical kinetics of isomerization reactions, and unbiased searches for molecules in the interstellar medium will be uses to illustrate the advantages of the spectrometer design.




Brooks H. Pate is the William R. Kenan, Jr. Professor of Chemistry at the University of Virginia. He is also the Director of the Astrochemistry in Charlottesville, headquarted at the University of Virginia. He received his B.S. in Chemistry from the University of Virginia in 1987 and his Ph.D. in Chemistry from Princeton University in 1992. He was an NRC Postdoctoral Fellow in the Molecular Spectroscopy Division at the National Institute of Standards and Technology from 1991-1993. His research interests include vibrational dynamics and the spectroscopy of highly excited molecules. He has published papers in the most prestigious and widely read journals of Chemistry, Chemical Physics, and Molecular Spectroscopy. Dr. Pate was the recipient of the Camille and Henry Dreyfus New Faculty Award in 1993, the NSF CAREER Award in 1996, and the Coblentz Award in 1999. In addition, he was selected as a Camille Dreyfus Teacher Scholar in 1998, a MacArthur Fellow in 2001, and a Fellow of the American Physical Society in 2008.