Revisiting the Formation of HeH$^+$ in the Planetary Nebula NGC 7027
  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 computed. Good agreement is found between our
new calculations and prior results obtained two decades ago for kinetic
temperatures between $\sim$800 and 20,000 K. This finding is inconsistent with
a recent claim in the literature of a wide variation in published values and
establishes the robustness of our knowledge of this process for the formation
of HeH$^+$. The implications of the current results to the first detection of
HeH$^+$ and its modeled abundance in the planetary nebula NGC 7027 are
discussed.
