Laboratory Measurements of N2 Reacting with H3+ Isotopologues and Implications for Deuterated Astrochemistry

Columbia University, New York NY

Investigators

Abstract

Molecular observations are important to understanding how the interstellar gas is converted to molecular clouds, stars, and planets. This research project will investigate the formation of the molecular ions N2H+ and N2D+, which are commonly used to trace properties of prestellar molecular clouds and protoplanetary disks. By means of a sophisticated laboratory experiment, the investigators will accurately determine the production rates of the ions at the very low temperatures relevant to interstellar clouds. Results from the study will allow astronomers to accurately determine the abundance of these ions in space and interpret observations of the earliest stages of star and planet formation. This project will contribute to the training and professional development of a postdoctoral scholar, provide research opportunities for undergraduates, and engage the public through lectures on astrochemistry. Using a dual-source, merged fast-beams apparatus, Savin and collaborators will measure accurate integral cross sections (ICS) for six reactions of N2 with H3+ and its deuterated forms as a function of the internal temperature of the reactants. The ICSs will allow the team to generate reliable thermal rate coefficients for N2H+ and N2D+ formation for use in astrochemical models. The measurements will also guide astrochemical models of deuterated molecules for which laboratory data are unavailable, and they will test the validity of approximations used to interpret branching fractions of partially deuterated molecules in space. 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.