Rate constants for the H+ + H2 reaction from 5 K to 3000 K with a statistical quantum method

Abstract

Paper published as part of the special topic on Quantum Dynamics with ab Initio Potentials ARTICLES YOU MAY BE INTERESTED IN Quantum and quasiclassical dynamical simulations for the Ar 2 H + on a new global analytical potential energy surface

Collisional cooling of primordial and interstellar media by H2

“…For the purpose of this illustration, the cosmological model of Flower & Pineau des Forêts (2000) was adopted. It may be seen from the Figure that the freeze-out value of the ortho:para ratio increases by a factor of more than 2 when the data of González-Lezana et al (2021) are used. The computed fractional abundance of H + at freeze-out is x(H + ) ≈ 3 × 10 −4 .…”

“…The phenomenon of freeze-out is illustrated in Fig. 9, where the ortho:para ratio is plotted as a function of redshift, adopting either the H + -H2 rate coefficients of Gerlich (1990), which were used by Le Bourlot et al (1999), or the more recent data of González-Lezana et al (2021). For the purpose of this illustration, the cosmological model of Flower & Pineau des Forêts (2000) was adopted.…”

“…We note that collisions with He are of secondary importance, owing to its fractional abundance being lower than that of H and/or H2 and the absence of ortho ↔ para inter-conversion. For excitation by H + , we use the data of González-Lezana et al (2021) for the temperature range 5 < T < 3000 K and 26 levels of H2 with energies up to E(v = 2, J = 3) = 12550 K.…”

Benchmarking an improved statistical adiabatic channel model for competing inelastic and reactive processes

“…where A ≡ C, S, D, H and B ≡ H , and typically involving some competition between inelastic (1), exchange (2) and insertion processes (3). These collisions involve molecular hydrogen, which can occur as 2 different nuclear spin isomers: ortho-and para-H 2 , with total nuclear spin quantum numbers, I = 1 and I = 0 respectively 29,30 . Because the nuclear wavefunction for the collisional system has to obey the proper exchange symmetry with respect to identical nuclei, o-H 2 can only occur with odd rotational quantum numbers, while p-H 2 is characterized by even values for j.…”

Benchmarking an improved statistical adiabatic channel model for competing inelastic and reactive processes

“…(1), exchange (2) and insertion processes (3). These collisions involve molecular hydrogen, which can occur as 2 different nuclear spin isomers: ortho-and para-H 2 , with total nuclear spin quantum numbers, I = 1 and I = 0 respectively 29,30 . Because the nuclear wavefunction for the collisional system has to obey the proper exchange symmetry with respect to identical nuclei, o-H 2 can only occur with odd rotational quantum numbers, while p-H 2 is characterized by even values for j.…”