Theoretical studies of mutual neutralization in collisions of Li⁺ + F¯ and He⁺ + H¯

Molecular Physics seminar

Monday 01 June 2015
from 10:00
to 11:00 at
FB55

Speaker :

Sifiso Nkambule (Kemisk Fysik)

Abstract :

In this talk I will give an overview of the mutual neutralization reactions involving small systems that are currently studied by our research group. The reactions are mutual neutralization in collisions of Li⁺ + F¯ and He⁺ + H¯. Both reactions involve a transfer of charge and they occur at low collision energies. Employing quantum chemistry and electron scattering calculations, the electronic states involved in the reactions and their couplings are computed. In the LiF system, a set different quantum chemistry calculations are performed and we investigate their influence on the curve crossing distance and the cross section. In the HeH system, the electronic structure calculation is combined with electron scattering calculation at short internuclear distances. Here the potential energy of the ground state of HeH⁺ is found to lie below, in energy, to the potentials of the electronic states relevant in mutual neutralization and hence there is a possibility of autoinisation. Autoinisation widths are computed and included in the nuclear Schrödinger equation using the “local Boomerang model”. The nuclear dynamics are studied using time-independent quantum techniques. In the case of LiF, a semi-classical Landau-Zener study is also performed. Reaction cross sections are then computed and compared with other theoretical and measured data available.