Excited-state mixing in the optical pumping of alkali-metal vapors

The effect of excited-state mixing on the optical pumping of alkali-metal vapors is considered for the case where the energy separation between the P122 and P322 first excited states is relatively large, allowing the isolation of mixing effects within a particular J level. Two models for the mixing process are proposed, one a random reorientation of the total electronic angular momentum J, and the other a reorientation of J subject to the selection rule mJ=0, 2. The probabilities for mixing transitions among J-state sublevels have been calculated for an alkali atom of nuclear spin 32, and can be used to calculate the optical-pumping transition probabilities for a vapor subject to any degree of excited-state mixing. Several possible experiments suggested by these calculations are discussed. © 1966 The American Physical Society.