Measurement of theRb87-Xe129spin-exchange cross section

The ${}_{}{}^{87}{}_{}{}^{}\mathrm{Rb}$-${}_{}{}^{129}{}_{}{}^{}\mathrm{Xe}$ spin-exchange cross section has been measured in ${\mathrm{N}}_2$ buffered cells as a function of the ${\mathrm{N}}_2$ density using an alkali vapor magnetometer technique. The strong dependence of the spin-exchange cross section on the ${\mathrm{N}}_2$ density indicates a significant role for the Rb-Xe van der Waals molecule in the spin-exchange process. Our data have allowed us to estimate the Rb-Xe molecular formation rate, which is in reasonable agreement with previous measurements. The extrapolated binary spin-exchange cross-section term is found to be ${\sigma }_{\mathrm{ex}}{\overline{V}}^2=1.5\mathrm{}\times {10}^{-10\mathrm{}}$ ${\mathrm{cm}}^4$ ${\sec }^{-2\mathrm{}}$.