Dipole moments and electric field gradients for correlated wavefunctions of NO: The X ²Π, A ²Σ⁺, and D ²Σ⁺ states

Recent experiments by Bergeman and Zare led to a dipole moment of |μ| = 1.10 ± 0.03 D for the υ = 3 vibrational level of the A²Σ⁺ state of NO, whereas configuration interaction (CI) studies by Green led to μ = 0.39 D (N⁺O^-), a serious discrepancy. We report herein ab initio generalized valence bond (GVB) and GVB CI calculations resulting in a dipole moment of +1.36 at R_e for the A²Σ⁺ state; considering the expected decrease of μ for increasing υ, this is in reasonable agreement with experiment. Theoretical values of the dipole moment, electric field gradient, and excitation energies are reported for the X²Π, A²Σ⁺, and D²Σ⁺ states of NO.