Multiconfiguration selfhyphen;consistenthyphen;field calculation of the dipole moment function and potential curve of NO(X2Pgr;)

摘要

The electronic dipole moment function, potential energy curve, and other oneminus;electron properties of the2Pgr; ground state of NO have been calculated fromR= 1.6 toR= 3.4 bohr by the optimized valence configurations (OVC) multiconfiguration selfminus;consistentminus;field method. At internuclear separations only 0.6minus;0.7 bohr larger thanRe, the ground state wavefunction is found to exhibit a nearly equal mixing of electronic configurations corresponding to theX2Pgr; andB2Pgr; states of NO. This behavior and its manifestations in the OVC framework are discussed in detail. The theoretical OVCminus;MCSCF dipole curve is shown to be consistent with available experimental data in that (1) its first derivative nearReof 1.10 D/bohr is in excellent agreement with that deduced from observed infrared intensities, and (2) thev= 0 dipole expectation value obtained from the computed moment function and accurate vibrational wavefunctions is minus;0.139 D (Nminus;O+), which is within 0.02 D of the Stark effect microwave result of plusmn;0.158 D. A comparison of the calculated potential curve with an accurate RKR potential for NO (X2Pgr;) indicates relative congruency to within 0.06 eV over the full range of inernuclear separations spanning the turning points of thev= 25 vibrational level. Comparisons with previous theoretical treatments of this molecule are also presented.