Ion chemistry in the early universe: revisiting the role of HeH+ with new quantum calculations

Abstract

The role of HeH+ has been newly assessed with the aid of newly calculated rates which use entirely ab initio methods, thereby allowing us to compute more accurately the relevant abundances within the global chemical network of the early universe. A comparison with the similar role of the ionic molecule LiH+ is also presented. Quantum calculations have been carried out for the gas-phase reaction of HeH+ with H atoms with our new in-house code, based on the negative imaginary potential method. Integral cross sections and reactive rate coefficients obtained under the general conditions of early universe chemistry are presented and discussed. With the new reaction rate, the abundance of HeH+ in the early universe is more than one order of magnitude larger than in previous studies. Our more accurate findings further buttress the possibility to detect cosmological signatures of HeH+.

Astronomy and Astrophysics, in press

References in corpus (6)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Nucleosynthetic signatures of the first stars
• Effects of primordial chemistry on the cosmic microwave background
• Vibrational level population of H${}_2$ and H${}_2^{+}$ in the early Universe
• Fast LiH destruction in reaction with H: quantum calculations and astrophysical consequences
• The first spectral line surveys searching for signals from the Dark Ages

Cited by in corpus (13)

• First astrophysical detection of the helium hydride ion (HeH${}^{+}$)
• The Dawn of Chemistry
• The Small-Scale Dynamo and Non-Ideal MHD in Primordial Star Formation
• Detection of vibrational emissions from the helium hydride ion (HeH${}^{+}$) in the planetary nebula NGC 7027
• New accurate measurement of 36ArH+ and 38ArH+ ro-vibrational transitions by high resolution IR absorption spectroscopy
• Non-thermal photons and H2 formation in the early Universe
• Revisiting the Formation of HeH${}^{+}$ in the Planetary Nebula NGC 7027
• Energy-transfer Quantum Dynamics of HeH${}^{+}$ with He atoms: Rotationally Inelastic Cross Sections and Rate Coefficients
• OH in the diffuse interstellar medium: physical modelling and prospects with upcoming SKA precursor/pathfinder surveys
• Thermal and Resonant Emission of Dark Ages Halos in the Rotational Lines of HeH${}^{+}$
• The H${}_2$${}^{+}$ + He proton transfer reaction: quantum reactive differential cross sections linked with velocity mappings
• Distortion of the CMB spectrum by the first molecules of the Dark Ages
• Global Signals of the First Molecules from the Dark Ages in the Presence of Primordial Magnetic Fields