Theoretical molecular structure and experimental dipole moment of cis-1-chloro-2-fluoroethylene

Abstract

The equilibrium geometry of cis-1-chloro-2-fluoroethylene has been evaluated using two different ab initio methods: the coupled-cluster (CC) approach and Møller–Plesset perturbation theory. Accurate predictions have been obtained. Using both methods, the dipole moment has been estimated numerically as energy derivative with respect to an applied electric field at zero field strength. The experimental dipole moment of cis-1-chloro-2-fluoroethylene has been determined by observing the Stark spectrum of the J=4_0,4←3_1,3 and J=4_1,3←4_0,4 transitions. The spectrum profile has been fitted to a model function computed as a sum of Lorentzian profiles over the hyperfine-Stark components, whose frequencies have been derived by diagonalizing the full rotational–quadrupole-Stark Hamiltonian matrix for each value of the applied electric field. Very good agreement between experimental and theoretical dipole moment has been obtained.