Abstract:
Rotational spectroscopy is a powerful tool for studying the structures and intramolecular dynamics of gas-phase molecules and also for enabling their detection in astronomical environments with radiotelescopes. Inspired by the structures and chemistry of the 300+ molecules identified outside the Solar System, my group uses rotational spectroscopy coupled with quantum chemical calculations to study reactive intermediates and molecules which display large-amplitude motion or other features of structural interest. In this talk I will discuss several examples of molecules we have studied in recent years, including the beta-cyanovinyl radical, methyl tert-butyl ether, and various nitrogen-containing cyclic molecules, as well as broadband rotational spectra of the products of electrical discharges consisting of unsaturated nitrogen-containing precursors. Time permitting, I will also discuss our efforts to put a new twist on CRESU experiments (CRESU is a French acronym which translates to "Reaction Kinetics in a Uniform Flow"). CRESU has been a workhorse method for studying low-temperature gas-phase kinetics for radical reactions of interest in astrochemistry and it is centered around the use of a de Laval nozzle to produce a uniform molecular beam. I will discuss the prospects of incorporating optical detection methods within so-called "extended" de Laval nozzles which have been recently presented in the literature.
Bio:
Kyle Crabtree earned a B.S. in chemistry at Ball State University in 2006. He obtained his Ph.D. under Dr. Benjamin McCall at the University of Illinois, Urbana-Champaign, where he used high-resolution infrared spectroscopy to study astrochemically relevant ions, including H3+. For this work he received a NASA Earth and Space Fellowship in 2011. Upon completing his Ph.D. in 2012, he received a CfA Postdoctoral Fellowship at the Harvard Smithsonian Center for Astrophysics. There he worked with Dr. Michael McCarthy and measured the pure rotational spectra of several reactive molecules of both fundamental and astrochemical interest using Fourier transform microwave spectroscopy. Dr. Crabtree was appointed to the faculty at the University of California, Davis in 2014 where he is currently an associate professor. His group uses infrared and microwave spectroscopic techniques coupled with quantum chemical calculations to study the structure and reactivity of radicals and other molecules of astrochemical interest. He was the recipient of an NSF Faculty Early Career Development (CAREER) award in 2021 and the 2022 AAS Laboratory Astrophysics Division Early Career award, and served as an officer of the American Chemical Society Astrochemistry subdivision from 2020-2024.