Spin—Orbit Effects and the Fine Structure in the 3Σg− Ground State of O2

Abstract

The true microscopic Hamiltonian is used for the spin—orbit interaction in the description of the fine structure of the O2 3Σg− ground state. The inclusion of the true spin—orbit interaction Hamiltonian in place of the commonly used isotropic form AL·S causes a mixing of 1Σg+ into the ground state. The 1Σg+ character causes Hso to contribute to the same order to the effective spin dipole—dipole parameter λe as does the spin dipole—dipole Hamiltonian Hss and also results in slight changes in the experimental values of the spin—rotation coupling constant and the g value of the orbital angular momentum. The amount of 1Σg+ character is estimated to be 1.0×10−4 from the data of Tinkham and Strandberg, and a somewhat larger value 3.6×10−4 from the data of Bowers et al., these are to be compared with 1.3×10−4 obtained by a previous calculation. The amount of singlet character, obtained from a combination of experimental data and estimates of molecular parameters, is compatible with the experimental data obtained by Tinkham and Strandberg or Bowers et al. Our result is supported by agreement with a calculation of 〈Hss〉 and by comparing the values of this parameter for several 3Σ− molecules.

Fine structure and centrifugal distortion in the electronic and microwave spectra of O2and SO

“…The good agreement is re-established if one assumes that A (2) accounts for 20 per cent of A for SO and for less than 5 per cent for 02. These results are, however, contradicted by ab initio calculations [15,16] which claim that A (2) yields the dominant contribution to A for both 02 and SO. The search for important neglected terms in equation (8) was unfruitful, and a more accurate expression for the third-order terms which contains a summation over the vibrational levels of the 1Z state did not remove the discrepancy since that of equation (8) yields a minimum value.…”

High-Resolution Study of theX21 →X10+Fine-Structure Transition of BiF

“…The main contribution to the spin-spin coupling parameter l £ of a molecule in a 3 S 0 state arising from a p 2 configuration is from spin-orbit mixing with the 1 S / state derived from the same configuration (21). The V Å 0 / component of the 3 S 0 state is pushed below the V Å {1 components by an amount which corresponds to 02l.…”

A Rotational and Hyperfine Analysis of the [14.0]2Σ+–X2Σ+Band System of Cobalt Monocarbide

“…The rms errors for these fits are 0.0301 and 0.0150 cm 01 , respectively, which are an order of magni-H spin-rot tude worse that the fits for the other vibrational bands. Again Å 01.05 1 10 04 B y [17] we feel that further data are needed before we can unravel the perturbations affecting this vibrational level.…”

“…form of the true spin-rotation interaction Hamiltonian is, ponents can be fit separately, however, giving B values of the F 1 and F 2 subband components of 0.5110 and 0.5151 for a diatomic molecule (16)(17)(18) cm 01 , respectively. The rms errors for these fits are 0.0301 and 0.0150 cm 01 , respectively, which are an order of magni-H spin-rot tude worse that the fits for the other vibrational bands.…”