Revisiting the Formation of HeH${}^{+}$ in the Planetary Nebula NGC 7027

R. C. Forrey, J. F. Babb, E. D. S. Courtney +2

From four independent calculations using three different theoretical approaches, rate coefficients for the formation of HeH${}^{+}$ via the radiative association of He${}^{+}$ and H were c…