Microwave spectrum, quadrupole coupling, and barrier to internal rotation of 1-chloro-1-fluoroethane

Abstract

The microwave spectra of the ground state of the 35Cl and 37Cl isotopic species of 1-chloro-1-fluoroethane have been investigated in the K-band region. An analysis of the 35Cl quadrupole splittings shows that the χ tensor is asymmetric, presumably owing to the partial double bond character of the C–C1 bond. A satellite spectrum of the 35Cl isotope has been assigned to the first excited state of the torsion. The relative intensity of the satellite spectrum leads to a value of the barrier hindering internal torsion of 4300±300 cal/mole.