The calculation of the electric dipole moment of CO

Abstract

The electric dipole moment of CO determined by the molecular Hartree–Fock function of Huo is calculated to be +0.15 D (C+O−), while a configuration interaction wave function built from this molecular Hartree–Fock function plus 138 doubly substituted and 62 singly substituted configurations gives an electric dipole moment of –0.17 D (C−O+). This value is in good agreement with the experimentally observed value of –0.12 D (C−O+) and confirms the sign of the dipole moment which was deduced from a microwave experiment by Rosenblum, Nethercot and Townes. In perturbation language we have calculated the second-order contribution to ∞z∞ (the first-order contribution is zero). The contribution coming from doubly substituted configurations is small; the contribution of the singly substituted configurations is relatively more important. The relatively large error given by the Hartree–Fock function is due to the near cancellation of electronic and nuclear contributions to the electric dipole moment of CO.