Eur. Phys. J. D 58, 95-104 (2010)
https://doi.org/10.1140/epjd/e2010-00072-1

III. Electron-impact dissociative ionization of C₂ H₂⁺ and C₂ D₂⁺

¹ Université Catholique de Louvain, Institute of Condensed Matter and Nanosciences, Chemin du Cyclotron 2, 1348 Louvain-la-Neuve, Belgium
² Faculty of Physics, P.O. Box 386, 11000 Belgrade, Serbia
³ Institute of Physics, P.O. Box 68, 11081 Belgrade, Serbia
⁴ Durham University, Department of Chemistry, South Road, Durham, DH1 3LE, UK

Corresponding author: julien.lecointre@uclouvain.be

Received: 27 November 2009
Revised: 26 February 2010
Published online: 23 March 2010

Abstract

Absolute cross-sections for electron-impact dissociative ionization of C₂ H₂⁺ and C₂ D₂⁺ to CH⁺, C⁺, C₂⁺, H⁺, CH₂⁺ and C₂D⁺ fragments are determined for electron energies ranging from the corresponding threshold to 2.5 keV. Results obtained in a crossed beams experiment are analyzed to estimate the contribution of dissociative ionization to each fragment formation. The dissociative ionization cross sections are seen to decrease for more than an order of magnitude, from CH⁺ (5.37±0.10)×10^-17 cm² over C⁺ (4.19± 0.16)×10^-17 cm², C₂D⁺ (3.94±0.38)× 10^-17 cm², C₂⁺ (3.82±0.15)×10^-17 cm² and H⁺ (3.37±0.21)×10^-17 cm² to CH₂⁺ (2.66±0.14)×10^-18 cm². Kinetic energy release distributions of fragment ions are also determined from the analysis of the product velocity distribution. Cross section values, threshold energies and kinetic energies are compared with the data available from the literature. Conforming to the scheme used in the study of the dissociative excitation of C2 H2+(C2D2+), the cross-sections are presented in a format suitable for their implementation in plasma simulation codes.