Theoretical probation of FClCO⋯Cl 2 molecular complex : Post Hartree-Fock studies on molecular structures, stabilities and vibrational harmonic frequencies

Abstract

Potential energy surfaces of the weak FClCO⋯Cl 2 complex were studied using ab initio post Hartree-Fock theory at the MP2 and MP4 levels with 6-311G(d) and 6-311G(2d) basis sets. Two minimum energy conformations, first-order transition state and two second-order transition structures were found. The minimum energy forms (C and T) are separated by a small (less than 0.5 kcal mol ) barrier. At the MP2/6-311G(d) level their relative stabilities amount to −0.63 and −0.60 kcal mol for C and T conformers, respectively, where at the MP2/6-311G(2d) approximation stabilities of both forms rise to −1.09 and −1.21 kcal mol . The harmonic vibrational frequencies were calculated and compared with available experimental data.