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

The equilibrium geometry of cis-1-chloro-2-fluoroethylene has been evaluate d using two different ab initio methods: the coupled-cluster (CC) approach and Moller-Plesset perturbation theory. Accurate predictions have been obta ined. Using both methods, the dipole moment has been estimated numerically as energy derivative with respect to an applied electric field at zero fiel d 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 ov er the hyperfine-Stark components, whose frequencies have been derived by d iagonalizing the full rotational-quadrupole-Stark Hamiltonian matrix for ea ch value of the applied electric field. Very good agreement between experim ental and theoretical dipole moment has been obtained.