L'électroionisation dissociative du Dioyde de Carbone par impact d'électrons lents. Les canaux de dissociation conduisant à C+, O+ et CO+.

peer reviewedThis work reports the dissociative ionization of CO2 between 19-40 eV. The three dissociation channels producing C+, O+ and CO+ are examined in detail. Translational energy distributions as a function of the impinging electron energy and the ionization efficiency for fixed kinetic energy carried away by the fragments are measured. The kinetic energy versus appearance energy diagram is obtained for the three fragment ions. When available, the present results are compared with previous measurements. The lowest appearance energy of O+ and CO+ corresponds to the predissociation of the CO2+ (C2Sigma +/g) state. At higher energies all the fragment ions are exclusively produced by the dissociative ionization of CO2 in the multiple electron transition (MET) states. Predissociation is most probably the dominant mechanism. Each MET state branches off to produce not only the three fragments but also the same fragment in two different states. This is observed for each dissociation channel, i.e. O+, CO+ and/or C+. In the latter channel no evidence is found for the dissociative ionization reaction CO2+->C++2O