Formation, structure, and dissociation dynamics of CO 2 q+ (q≤3) ions due to impact of 12-keV electrons

Abstract

The electron-impact multiple ionization and subsequent dissociation of CO 2 is studied for 12-keV electron energy using a linear time-of-flight mass spectrometer coupled with a multihit, position-sensitive detector. The complete as well as incomplete Coulomb explosion pathways for CO 22 + and CO 23 + ions are examined and identified. The kinetic energy release distributions for these precursor ions are obtained. The experimental kinetic energy release values for the complete Coulomb fragmentation channels are found to be overestimated by those calculated from the Coulomb explosion model. From the angular correlation studies, it is inferred that bent geometrical states are involved for most of the fragmentation channels of CO 22 + and CO 23 + ions. The concerted and/or sequential nature of all the dissociation pathways is also assigned. This study provides the first results on energetics associated with the charge separation in dissociative ionization of CO 2 under the impact of electrons at a subrelativistic energy. © 2012 American Physical Society.