Experimental determination of the rate constants for spin exchange between optically pumped K, Rb, and Cs atoms andXe129nuclei in alkali-metal–noble-gas van der Waals molecules

By analyzing the measured spin-relaxation transients of ${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}$ nuclear spins and alkali-metal-atomic spins in mixtures of alkali-metal-atom vapors, Xe gas, and larger amounts of ${\mathrm{N}}_2$ gas, we have determined the three-body formation rates and the spin-transfer probabilities for alkali- metal–noble-gas van der Waals molecules. Three parameters, in addition to the spin quantum numbers of the alkali-metal and noble-gas nuclei, are needed to predict the spin-transfer rates. These parameters, which we have determined from experimental measurements, are x=γN/α, the ratio of the spin-rotation interaction γN to the spin-exchange interaction α; $p_0$, the third-body pressure for which the molecular breakup rate ${\tau }^{\mathrm{-}1}$ is equal to the spin-rotation frequency γN/h; and Z, the three-body rate constant for forming van der Waals molecules.