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Laboratory and Possible Interstellar Detection of trans-Methyl Formate

Thursday, January 7, 2010 - 4:30pm

"Astrochemistry at High Resolution" Conference

Jodrell Bank Center for Astrophysics, Manchester, UK


Anthony J. Remijan

Assistant Scientist

ALMA Commissioning and Science Verification

National Radio Astronomy Observatory, Charlottesville, VA 22903

Tel: (434) 244-6848; Fax: (434) 296-0278





The rotational spectrum of the trans conformational isomer of methyl formate has been assigned using pulsed jet spectroscopy. A total of 28 transitions, 19 from the A-symmetry torsional state and 9 from the E-symmetry torsional state, have been detected in the laboratory. This spectrum was expected to have strong internal rotor effects due to a low three-fold barrier to methyl group internal rotation, calculated to be around 20 cm-1. The population of this conformer, which lies approximately 2000 cm-1 higher in energy than the previously assigned cis conformer, was enhanced through the use of an electric discharge. Transitions were found by a combination of chirped-pulse Fourier transform microwave spectroscopy, a high-sensitivity Fourier transform microwave spectrometer, and microwave- microwave double resonance spectroscopy to confirm quantum state connections. A total of seven transitions (four from the A-symmetry torsional state and three from the E) have been identified in absorption in Green Bank Telescope survey scans towards Sgr-B2(N) as part of the GBT PRIMOS Project,, showing an abundance relative to the cis conformer that is much higher than the relative energies would predict. This detection could offer insight into the production mechanism of methyl formate in the interstellar medium.




Anthony J. Remijan is an Assistant Scientist in charge of ALMA Commissioning and Science Verification for the National Radio Astronomy Observatory (NRAO). He received his B.S. in Astronomy from the University of Illinois at Urbana-Champaign in 1996, his M.S. in Astronomy from Iowa State University in 1998, and a Ph.D. in Astronomy from University of Illinois at Urbana-Champaign in 2003. He was a postdoctoral research associate at NASA Goddard Space Flight Center from 2004-2006 and an ALMA postdoctoral research associate at NRAO from 2006-2008. His research interests include the discovery and study of interstellar molecules via radiotelescope observations, broadband mm-wave spectroscopy measurements and spectral analysis, and generally, the interplay between physics, astronomy, chemistry, and biology. His ambition for teaching is demonstrated by the variety of courses he has taught at the University of Maryland-University College (Introduction to Astronomy; Introduction to Physical Science; Introduction to Physical Science Laboratory), Prince George's Community College (Introduction to Astronomy), Parkland College (The Solar System; Stars, Galaxies, and the Universe; General Physics I; General Physics II; Mechanics; Electricity and Magnetism; Modern Physics), and Illinois State University (Atoms to Galaxies; Physics for Science and Engineering I; Physics for Science and Engineering II; Statics). His ambition for public outreach is demonstrated by the wide variety of public lectures he has given to promote the sciences of astrochemistry and astrobiology, speaking in venues as diverse as the Science Center at the Robert C. Byrd Green Bank Telescope facility in Green Bank, WV to the 12th Annual Coalition for National Science Funding (CNSF) Exhibition & Reception on Capitol Hill. Dr. Remijan was the recipient of the University of Illinois Excellent Teaching Award in 1998, the Iowa State University Richard G. Patrick Award for Outstanding Teaching Assistant in 1998, the Iowa State University Teaching Excellence Award in 1998, the Iowa State University Outstanding First-Year Teaching Award in 1997, and the University of Illinois Excellent Teaching Award in 1995.