dc.creator Stewart, Jacob T. en_US dc.creator Brumfield, Brian E. en_US dc.creator Gibson, Bradley M. en_US dc.creator McCall, Benjamin J. en_US dc.date.accessioned 2012-07-09T19:12:48Z dc.date.available 2012-07-09T19:12:48Z dc.date.issued 2012 en_US dc.identifier 2012-FB-05 en_US dc.identifier.uri http://hdl.handle.net/1811/52258 dc.description Author Institution: Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801; Departments of Chemistry and Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801. en_US dc.description Brian E. Brumfield present address: Department of Electrical Engineering, Princeton University, Princeton, Nj 08544 en_US dc.description.abstract Supersonic expansions are a useful tool for cooling molecules in the gas phase. While translational and rotational degrees of freedom can generally be cooled to low temperatures ($&lt;$30 K) using this technique, there has been conflicting evidence concerning the cooling of vibrational degrees of freedom. This cooling is particularly important for gas-phase absorption spectroscopy of large molecules with many vibrational degrees of freedom, such as buckminsterfullerene (C$_{60}$). We have attempted gas-phase infrared spectroscopy of C$_{60}$ by producing C$_{60}$ vapor in a hot ($\sim$900 K) oven and seeding the vapor in an argon supersonic expansion, but have been unable to observe any absorption signal. We attribute this to insufficient cooling of vibrational degrees of freedom in the expansion. In contrast, we have performed a similar experiment with pyrene (C$_{16}$H$_{10}$) heated to $\sim$430 K, which yielded rotationally-resolved spectra and an estimated vibrational temperature of 25-90 K. We will discuss these results and possible methods to obtain gas-phase absorption spectra of C$_{60}$. en_US dc.language.iso en en_US dc.publisher Ohio State University en_US dc.title VIBRATIONAL COOLING OF LARGE MOLECULES IN SUPERSONIC EXPANSIONS: THE CASE OF C$_{60}$ AND PYRENE en_US dc.type Article en_US dc.type Image en_US dc.type Presentation en_US
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