A MULTICONFIGURATION SELF-CONSISTENT-FIELD RESPONSE STUDY OF ONE-PHOTON AND 2-PHOTON DIPOLE TRANSITIONS BETWEEN THE X(1)SIGMA(+) AND A-(1)PI STATES OF CO

The one- and two-photon dipole transitions between the X 1Σ+ and the A 1Π states of CO have been studied by means of multiconfiguration self-consistent-field linear and quadratic response methods. The vibrationally averaged oscillator strength for the 0-0 one-photon dipole transition between the X 1Σ + and A 1 IΠ states obtained using the linear response method is 1.31x10-2 as compared to the experimental results of 0.96(14)x10-2, 1.08(7)x10-2, and 1.11x10-2. The two-photon transition probability rate constant, obtained using the quadratic response method, for the 0-1 vibrational band of the X-A transition of 7x10 -59 cm4 s is more than six orders of magnitude smaller than the experimental result of 3.5x10-52 cm4 s. We suggest that the experiment should be reconsidered. The dipole moment of the A 1Π state obtained from quadratic response calculations on the ground state at R=2.332 a.u. is -0.0441 a.u. suggesting an anomalous polarity also for the A 1Π state. The experimental value is ±0.059(20) a.u. © 1995 American Institute of Physics.