MCSCF calculation of the dipole moment function of CO

Potential energy and dipole moment functions for the ground state of CO have been calculated using MCSCF wavefunctions. Some difficulties with the MCSCF method at large distances, which are due to the near degeneracy of the two asymptotic states, are discussed. From the theoretical dipole moment function and the RKR potential function vibrational dipole matrix elements have been evaluated. For the fundamental and first overtone sequences, the theoretical values are in excellent agreement with experimental data. For transitions involving large vibrational quantum numbers (ν″ > 25) the calculated matrix elements are expected to be the most reliable ones presently available.