BEGIN:VCALENDAR VERSION:2.0 PRODID:Data::ICal 0.22 BEGIN:VEVENT DESCRIPTION:Brooks Pate\, UVA - Chemistry\n\n
\n Until about 2005\, molec ular rotational spectroscopy was performed using narrowband (~1 MHz) excit ation of a low-pressure gas in a resonant cavity. \; This method offer s high sensitivity for each data acquisition\, but the time required to pe rform a spectrum scan over about 10 GHz\, needed to capture the rotational spectrum\, was a major limitation to applications of the technique. \ ; Advances in high-speed digital electronics have made it possible to desi gn spectrometers that offer instantaneous\, broadband (>\; 10 GHz) perfo rmance. \; During our initial work with high-speed arbitrary waveform generators and digitizers (with Tom Gallagher) we developed the method of chirped pulse Fourier transform rotational spectroscopy that uses a pulse with linear chirp to phase-reproducibly excite the gas sample. \; The subsequent coherent emission (free induction decay) is detected with the h igh-speed digitizer and the frequency domain spectrum is obtained using FF T analysis. \; Since the introduction of the technique in 2008 [1]\, t he method has been applied to unimolecular reaction dynamics [2]\, the str uctures of molecular clusters [3]\, and the laboratory identification of m olecules in the interstellar medium \;[4]. \; The technique has be en extended to mm-wave spectroscopy with applications to Rydberg spectrosc opy [5]\, chemical reaction dynamics\, and analytical chemistry. \; Th e broadband technique has also enabled a new generation of molecular struc ture studies in the field of chirality [6] with the potential for solving significant challenges for real-time pharmaceutical manufacturing.
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\n\n References
\n\n [1] G.G. Brown\, B.C. Dian\, K.O. Douglass\, S.M. Geyer\, and B.H. Pate\, &ldquo\;A Broadband Fo urier Transform Microwave Spectrometer Based on Chirped Pulse Excitation&r dquo\; Rev. Sci. Instrum. 79\, 053103 (2008).
\n\n [2] B.C. Dian\, G.G. Brown\, K.O. Douglass\, and B.H. Pate\, &ldquo\;Measu ring Picosecond Isomerization Dynamics via Ultra-broadband Fourier Transfo rm Microwave Spectroscopy&rdquo\;\, Science 320\ , 924-928 (2008).
\n\n [3] C. Pé\;rez\, M.T. Muckle\, D.P. Zal eski\, N.A. Seifert\, B. Temelso\, G.C. Shields\, Z. Kisiel\, and B.H. Pat e\, &ldquo\;Structures of Cage\, Prism\, and Book Isomers of Water Hexamer from Broadband Rotational Spectroscopy&rdquo\;\, Science 336\, 897-901 (2012).
\n\n [4] D.P. Zaleski\, N.A. Seifert \, A.L. Steber\, M.T. Muckle\, R.A. Loomis\, J.F. Corby\, O. Martinez\, Jr .\, K.N. Crabtree\, P.R. Jewell\, J.M. Hollis\, F.J. Lovas\, D. Vasquez\, J. Nyiramahirwe\, N. \; Sciortino\, K. Johnson\, M.C. McCarthy\, A.J. Remijan\, and B.H. Pate\, &ldquo\;Detection of E-cyanomethanimi ne towards Sagittarius B2(N) in the Green Bank Telescope PRIMOS Survey&rdq uo\;\, Ap. J. Letters\, 765\, L10 (2013).
\n< p>\n [5] K. Prozument\, A.P. Colombo\, Y. Zhou\, G.B. Park\, V.S. Petrovic \, S.L. Coy\, and R.W. Field\, &ldquo\;Chirped-pulse Millimeter-wave Spect roscopy of Rydberg-Rydberg Transitions&rdquo\;\, Phys. Rev. Lett. 107\, 143001 (2011).\n\n [6] D. Patterson\, M. Sc hnell\, and J.M. Doyle\, &ldquo\;Enantiomer-specific detection of chiral m olecules via microwave spectroscopy&rdquo\;\, Nature 497< /strong>\, 475 (2013).
\n DTSTART:20151023T193000Z LOCATION:Physics Building\, Room 204 SUMMARY:Broadband Molecular Rotational Spectroscopy for Chemical Dynamics a nd Molecular Structure END:VEVENT END:VCALENDAR