Calculated spectroscopic constants and the equilibrium geometry of HCCCl

Abstract

Making use of experimental values for the ground-state rotational constants of 12 different isotopomers and vibration–rotation coupling constants calculated by the coupled electron pair approximation (CEPA) an accurate equilibrium geometry has been determined for monochloroacetylene: r_e(CH)= 1.0605(5)Å, R_1e(CC)= 1.2030(2)Å and R_2e(CCl)= 1.6353(1)Å. The equilibrium dipole moment is calculated by CCSD(T) using a basis set of 165 contracted Gaussian-type orbitals: µ_e=–0.433 D.