Absolute cross sections and kinetic energy release distributions for electron-impact dissociative excitation and ionization of NeD+

Abstract

Absolute cross sections for electron impact dissociative excitation and ionization of NeD+ leading to the formation of singly and multiply charged products (D+, Ne+, Ne2+ and Ne3+) are reported, in the energy range from their respective thresholds to 2.5 keV. The animated crossed-beams method is used. For singly charged fragments, absolute cross sections are obtained separately for dissociative excitation and for dissociative ionization. Dissociative excitation is seen to be restricted to the low-energy range (<300 eV) and the D+ formation dominates over the Ne+ one. At the maximum (around 35 eV), absolute cross sections for dissociative excitation are found to be (3.6 ± 0.8) × 10−17 cm2 and (6.3 ± 1.4) × 10−17 cm2 for Ne+ and D+, respectively; the corresponding appearance energies are (9.1 ± 0.5) eV and (10.0 ± 0.5) eV. The absolute cross section for dissociative ionization (Ne++D+ formation) is found to be (7.1 ± 1.4) × 10−17 cm2, around 155 eV, and the threshold energy is (26.8 ± 0.5) eV. For multiply charged products, absolute cross sections are found, around the maximum, to be (5.4 ± 0.5) × 10−18 cm2 and (18.2 ± 2.6) × 10−20 cm2 for Ne2+ and Ne3+, respectively; the corresponding thresholds are (53.1 ± 1.0) eV and (132 ± 5) eV. Kinetic energy release distributions are determined for each detected ionic product. The presented potential energy curves correspond to dissociation channels, which are significant for the discussion of present results. At fixed electron energy, the cross sections for the various ionization channels are seen to decrease exponentially with the potential energy of each dissociated ion pair.