Investigation of the neutral and cation chloroacetone molecular structures and spectroscopic properties by ab initio and density functional theory methods

A theoretical study on the structural, electronic and spectroscopic properties for the isolated chloroacetone (C3H5OCl) and its molecular cation was performed with ab initio and density functional theory methods. Two conformers were found stable for the neutral molecule, where the structure with the chlorine atom on the edge of a gauche/cis conformation with respect to the methyl group is more stable by 1.0 kcal/mol in comparison with the trans conformation. As for the molecular cation, only the gauche conformation was found stable. Theoretical first adiabatic ionization potential and vibrational frequencies investigated are in very good agreement with the experimental results.