Advancing Interstellar Aromatic and Carbon-Based Chemistry: An Integrated Experimental, Theoretical, and Astronomical Approach

Carbon is an extraordinarily versatile chemical element due to its ability to form long chains and rings (i.e., catenation). This attribute is responsible for the incredible variety of organic compounds in nature as well as biology itself. While large carbon-based molecules such as polycyclic aromatic hydrocarbons (PAHs) and fullerenes are ubiquitous in space, an unexpectedly rich reservoir of smaller catenated carbon structures was recently discovered in nearby cold molecular clouds. The team will conduct a combined laboratory and theoretical effort (in coordination with sensitive radio observations) to obtain new spectra to identify new organic (ringed or otherwise) molecules, determine the chemical pathways by which five- and six-Carbon rings – building blocks of organic chemistry - form and eventually evolve into PAHs and more complicated structures. Laboratory work will take advantage of equipment upgrades as well as improved analysis/diagnostic tools and algorithms, many of which with applications outside of astronomy. This work will provide research experience for undergraduate and graduate students as well advancing the careers of two postdocs. Through a closely coordinated program of laboratory measurements, theoretical calculations, and astronomical observations, the research team will strive for a much deeper understanding of complex carbon chemistry, including the specific pathways that form small aromatic rings and the subsequent reactions that lead to much larger and complicated carbon catenates. The proposed research will have wide ranging implications, from the sources of the ubiquitous infrared and optical features seen along many different lines of sight, to the formation of stars and planets. The proposed laboratory studies will result in rapid, unbiased, and robust diagnostic tools to analyze complex mixtures de novo and provide critical tests of fundamental reactions and their product species. Both will have applicability in a wide range of scientific disciplines beyond their immediate astrochemical applications. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.