Simultaneous and Induced Electronic Transitions in Oxygen. I

Abstract

A fairly general theory of the relative intensities of the transitions ${}^1{\Delta }_g^1{\Delta }_g{\leftarrow }^3{\Delta }_g^{\text{−3}}{\Delta }_g^{-}$ and ${}^3{\Delta }_g^{\text{−1}}{\Delta }_g{\leftarrow }^3{\Delta }_g^{\text{−3}}{\Delta }_g^{-}$ in oxygen is given. The theory rests on the posulate that the terms in the above transitions mix with other bimolecular terms due to the intermolecular forces. Intermolecular exchange is shown to be essential for a successful interpretation of these transitions. Calculations are done neglecting the intermolecular overlap, but including all the electrons in the theory. All the allowed interactions, in the absence of intermolecular overlap, are considered in the theory. No assumption regarding the geometry of the O₂···O₂ pair is made. The theory predicts that relative oscillator strengths of the above two transitions (former to latter) should be 1.20. This is in excellent agreement with the experimental results. Theoretical predictions are shown to be unaffected when the intermoledular overlap is included in the calculations. The above results are derived from the ratios of interactions and thus are independent of approximations commonly used in the evaluation of integrals.