Postdoctoral Fellowship: AAPF: Improved Astrochemical Data for Diffuse Cloud Models: Theoretical Dissociative Recombination Rate Coefficients for OH+, H2O+, and H2Cl+

Josh Forer is awarded an NSF Astronomy and Astrophysics Fellowship to carry out a program of research and education at Columbia University. Forer will study microscopic chemical reactions that need to be understood to track the evolution of star-forming gas clouds in galaxies. Additionally, Forer will mentor summer research with the women's undergraduate institution Barnard College, participate in Columbia University's Astronomy Public Outreach program of free public talks, and teach high school students with a strong interest in math and physics. Forer will develop theory and code to describe the dissociative recombination (DR) of OH+, H20+, and H2Cl+ at scattering energies relevant to diffuse cloud temperatures. State-selected rovibronic kinetic DR rate coefficients (needed, but not available) of these ions will be produced to place constraints on the relative abundance of molecular hydrogen, the inferred cosmic-ray ionization rate of atomic hydrogen, and the interstellar radiation field. These constraints allow astrochemical models to map the transition of diffuse interstellar clouds from almost purely atomic to increasingly molecular — a crucial early step in star formation. 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.