$AB~INITIO$ HARTREE–FOCK AND DENSITY FUNCTIONAL THEORY INVESTIGATIONS ON THE POTENTIAL ENERGY SURFACE AND VIBRATIONAL SPECTRA OF DIETHYL SULFONE

Abstract

In this work, ab initio Hartree–Fock (RHF/6-311++G(d, p)) and density functional theory (B3PW91/6-311++G(d, p)) investigations on the potential energy surface (PES) and vibrational spectra of diethyl sulfone have been performed. It was found, that diethyl sulfone exists as an equilibrium mixture of four interconverting rotational isomers. The accurate energies of the four minima and the five saddle points located on PES were determined at the above mentioned levels of calculation. The relative populations of the stationary points found have been calculated using Boltzmann distribution law, considering the degeneracy of states. The theoretical IR spectra calculations for all stationary points on the PES have been done as well.