Structure and Vibrational study of Entrance Channel of Monomer C2H2+ Cl via ab initio calculation

Abstract

Theoretical calculations are reported to predict the geometrical structures and IR vibrational frequencies of entrance channel of C₂H₂+Cl interaction in the ground state. The calculations are performed via Ab initio calculations at perturbation theory (MP2) with Dunning correction-consistent basis set (aug-cc-pVDZ). The results show that attaching acetylene molecule with radical chlorine via van der Walls bonds has two equilibrium structures. These structures have IR active of harmonic vibrational frequencies. In one of these structures; Cl atom bonded to a particular H atom which has a single IR active of C-H asymmetric stretching vibration at 3428 cm^-1. The other structure, in which Cl atom attached to both of H atoms (T- shape), predicted harmonic vibration at 3424 cm^-1 for asymmetric C-H stretch. The rear geometrical structure is lower minimum energy than the former one by 11.78 KJ/mol. Finally, the barrier for the interconversion from one minimum to the other is also computed in this study.