Matrix isolation infrared and ab initio studies on conformers of fluoroacetic and chloroacetic acid

Abstract

The infrared spectra of matrix isolated fluoroacetic acid and chloroacetic acid were studied in solid Ar, Kr, and Xe matrices. The energies and spectra of possible conformers of fluoroacetic acid and chloroacetic acid were simulated by extensive ab initio calculations at the MP2/6-311G ** (energies, geometries), MP2/6-31G ** (barriers), and MP2/4-31G * (numerical frequencies) levels. The present calculations propose the existence of four distinct conformers. For fluoroacetic acid the two lowest energy conformers, i.e., Tt and Ct, were found to be present after deposition of the solids