High-Resolution Laser Spectroscopy of Astronomically Important Magnesium-bearing Organic Free Radicals

This research project seeks to study astronomically important metal-bearing free radicals, specifically magnesium-bearing carbon chains and clusters, through a combination of laboratory spectroscopic measurements, quantum chemical calculations, and theoretical spectroscopic modeling. Free radicals generated using laser ablation of metals followed by reactions with organic precursors will be cooled in a supersonic molecular beam yielding conditions analogous to those in the interstellar gas. State of the art laser techniques will then be used to record high resolution optical and infrared spectra of the free radicals, enabling their identification in space by means of sensitive spectroscopic surveys done with large powerful telescopes. This project will train a graduate student and a postdoctoral scholar in methods of advanced laboratory astrophysics. The research team will develop novel methods to produce magnesium-bearing carbon chains and clusters containing an odd number of carbon atoms, which are hypothesized to exist but await detection in the circumstellar envelopes of evolved carbon stars. After conducting vibrationally resolved spectral surveys using nanosecond pulsed lasers, the team will conduct rotationally resolved measurements using continuous-wave lasers to achieve unprecedented spectral detail on the target molecules. The team will then use sophisticated Hamiltonian models they developed to gain insight into non-Born-Oppenheimer interactions between the lowest energy electronic states of these molecules, particularly pseudo-Jahn-Teller and spin-orbit interactions that influence the energy level structure and intramolecular dynamics. The project would characterize fundamental molecules which play a central role in optical cycling, enabling advances in precision spectroscopy, low-temperature chemistry, tests of fundamental physics, and quantum information science. 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.