Low collision energy mutual neutralization reaction of He⁺ and H⁻

Abstract

A Semi-classical Landau-Zener model is employed to theoretically study mutual neutralization in the collisions of $\mathrm{^4He^+}$ and $\mathrm{H^-}$/$\mathrm{D^-}$. The model includes ten covalent states and an ion-pair state of $\mathrm{^2\Sigma^+}$ symmetry for the $\mathrm{HeH}$ molecular system. Here the assumption is that only two states are interacting at a given internuclear position. In the diabatic representation, the nuclear dynamics relevant for mutual neutralization is modelled for collision energies below 100 $\mathrm{eV}$. The mutual neutralization reaction cross section and final states distribution are computed and compared with previous theoretical and experimental results.

Studies of mutual neutralization in collisions involving Mg+/H−, Na+/H−, Li+/H− and Li+/Cl−

“…The neglected rotational and translational factors could also be contributing to the discrepancy. A discrepancy between the fully quantum study and the semi-classical model has recently been observed for the mutual neutralization of process [21] . The treatment of the radial velocity, , at the curve crossing classically leads to a wrong asymptotic dependence of the reaction cross section on , rather than [7] .…”

“…This is proving a challenge to adequately undertake, in particular for systems with many electrons. On the other hand, the Landau-Zener model [17] , [18] , can provide mutual neutralization reaction cross sections that are comparable with the fully quantum studies [16] , [19] , [20] , [21] . The Landau-Zener model is only dependent upon parameters like the asymptotic energies for the states involved, electronic couplings and the crossing distance.…”

“…The adiabatic to diabatic transformation is carried out using a transformation matrix, as outlined in refs. [11] , [19] , [21] . The two-by-two transformation matrix, T, is of the form where is defined a transformation rotational angle.…”