Electron-impact ionization and dissociation of C2D+

Abstract

Absolute cross sections for electron-impact single ionization, dissociative excitation and dissociative ionization of the ethynyl radical ion (C(2)D(+)) have been measured for electron energies ranging from the corresponding reaction thresholds to 2.5 keV. The animated crossed electron-ion beam experiment; is used and results have been obtained for the production of C(2)D(2+), C(2+), C(2)(+), CD(+), C(+) and D(+). The maximum of the cross section for single ionization is found to be (2.01 +/- 0.02) x 10(-17) cm(2), at the incident electron energy of 105 eV. Absolute total cross sections for the various singly charged fragments production are observed to decrease by a factor of almost three, from the largest cross-section measured for C(+), over C(2)(+) and CD(+) down to that of D(+) The maxima of the cross sections are obtained to be (14.5 +/- 0.5) x 10(-17) cm(2) for C(2)(+) (12.1 +/- 0.1) x 10(-17) cm(2) for CD(+) (27.7 +/- 0.2) x 10(-17) cm(2) for C(+) and (11.1 +/- 3.8) x 10(-17) cm(2) fo D(+). The smallest cross section is measured to be (1.50 +/- 0.04) x 10(-18) cm(2) for the production of the doubly charged ion C(2+). Individual contributions for dissociative excitation and dissociative ionization are determined for each singly-charged product. The cross sections are presented in closed analytic forms convenient for implementation in plasma simulation codes. Kinetic energy release distributions of dissociation fragments are seen to extend from 0 to 6 eV for the heaviest; fragment C(2)(+), up to 11.0 eV for CD(+) 14.2 eV for C(+) and 11.2 eV for D(+) products.