Dynamics of Electron Attachment and Ionization Processes in the CCl4 Molecule: An ab Initio MO and Direct Dynamics Study

Abstract

Electron attachment and ionization processes in the CCl4 molecule to form CCl4 radical anion and cation, CCl4 + e- (hole) → CCl4- (CCl4+), have been studied by means of both ab initio MO and direct dynamics calculations. The ab initio calculations of CCl4- show that two conformers of the radical anion CCl4- are obtained for the stable structures: the elongated and compressed structures distorted from Td symmetry of neutral CCl4 due to the Jahn−Teller effect. The elongated structure is more stable by 11.8 kcal/mol relative to the compressed structure at the MP4SDQ/6-31G(d) level. The CCl4+ is unstable relative to its dissociation limit (CCl3+ and Cl atom). The direct dynamics trajectory calculations show that the radical anion CCl4-, formed by a vertical electron attachment of the CCl4 molecule, leads directly to the elongated form of CCl4-. On the other hand, CCl4+ formed by a vertical ionization directly dissociates to CCl3+ + Cl without an activation barrier. The reaction mechanisms of electron attachment and ionization processes are discussed on the basis of theoretical results.