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

Abstract

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.

arXiv commentetable of rate coefficients available

References in corpus (8)

• First astrophysical detection of the helium hydride ion (HeH${}^{+}$)
• The chemistry of vibrationally excited H2 in the interstellar medium
• Ion chemistry in the early universe: revisiting the role of HeH+ with new quantum calculations
• Detection of vibrational emissions from the helium hydride ion (HeH${}^{+}$) in the planetary nebula NGC 7027
• Rovibrationally resolved photodissociation of HeH+
• Sturmian theory of three-body recombination: application to the formation of H${}_2$ in primordial gas
• Rate constants for the formation of SiO by radiative association
• Determination of photodissociation and radiative association cross sections from the same time-dependent calculation

Cited by in corpus (2)

• Energy-transfer Quantum Dynamics of HeH${}^{+}$ with He atoms: Rotationally Inelastic Cross Sections and Rate Coefficients
• Chemistry and ro-vibrational excitation of HeH${}^{+}$ in the Planetary Nebula NGC 7027