Eur. Phys. J. D (2017) 71: 106
https://doi.org/10.1140/epjd/e2017-70740-7

Regular Article

Rotationally inelastic cross sections, rates and cooling times for para-H₂⁺, ortho-D₂⁺ and HD⁺ in cold helium gas^*

¹ Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstr. 25/3, 6020 Innsbruck, Austria
² Institut für Experimentalphysik, Heinrich-Heine Universität Düsseldorf, Universtätsstr. 1, 40225 Düsseldorf, Germany

^a e-mail: francesco.gianturco@uibk.ac.at

Received: 27 November 2016
Published online: 18 May 2017

Abstract

In the present work we discuss the dynamical processes guiding the relaxation of the internal rotational energy of three diatomic ions, the para-H₂⁺, the ortho-D₂⁺ and the HD⁺ in collision with He atoms. The state-changing cross sections and rates for these Molecular Hydrogen Ions (MHIs) are obtained from Close Coupling quantum dynamics calculations and the decay times into their respective ground states are computed by further solving the relevant time-evolution equations. The comparison of the results from the three molecules allows us to obtain a detailed understanding, and a deep insight, on the relative efficiencies of the relaxation processes considered.