III. Electron-impact dissociative ionization of C 2 H 2 + and C 2 D 2 +

olute cross-sections for electron-impact dissociative ionization of C 2 H 2 + and C 2 D 2 + to CH + , C + , C 2 + , H + , CH 2 + and C 2 D + 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 cm 2 over C + (4.19± 0.16) × 10 -17 cm 2 , C 2 D + (3.94±0.38) × 10 -17 cm 2 , C 2 + (3.82±0.15) × 10 -17 cm 2 and H + (3.37±0.21) × 10 -17 cm 2 to CH 2 + (2.66±0.14) × 10 -18 cm 2 . 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 C 2 H 2 + ( C_2 D_2^+ ) , the cross-sections are presented in a format suitable for their implementation in plasma simulation codes.