Astronomy Colloquium for 2018-04-25

Series: Astronomy Colloquium
Date: Wednesday 25-Apr-2018
Time: 16:05-17:00 (4:05-5:00 pm)
Location: ATL 2400
Speaker: Dr. Brett McGuire (NOAO)
Title: From One to Two Dimensional Interstellar Carbon: A Synthesis of Laboratory, Observations, and Theory

In the last 50 years of astrochemical research, the realm of one-dimensional carbon chemistry (i.e. carbon chain molecules) has been well explored. Life, however, relies on two and three-dimensional carbon - branches, rings, bridges, and so forth. Here, we present the first rotational detection of a six-membered ring molecule in the interstellar medium (ISM), benzonitrile (c-C6H5CN), using deep Green Bank Telescope observations of TMC-1 combined with high-precision laboratory spectroscopy. We then explore the formation chemistry of this two-dimensional carbon molecule using a combined laboratory, quantum chemical, and modeling approach. We demonstrate the synthesis of cyclic species (benzene [c-C6H6] and benzonitrile) from simple, acyclic precursors, providing definitive evidence for facile bottom-up generation of two-dimensional carbon chemistry in the ISM. The results show that benzonitrile can already be used as a reliable proxy for the presence of benzene in the ISM, and that there may exist a much larger array of 'hidden' aromatic species just beyond the current sensitivity of spectral surveys.

Colloquia are usually preceded by espresso and ice cream at 1:45 pm outside room PSC 1150 and are followed by an informal reception at 5:15 pm in that room. Anyone interested in talking with the speaker, or being added to the colloquium announcement email list, should contact the colloquium organizer. Lunch will normally be reserved for the speaker to talk to graduate students.

Colloquium Organizer: Prof. L. Drake Deming


Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.


Directions and information about parking can be found here.

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