Collisional 3He and 129Xe Frequency Shifts in Rb-Noble-Gas Mixtures

The Fermi-contact interaction that characterizes collisional spin exchange of a noble gas with an alkali-metal vapor also gives rise to NMR and EPR frequency shifts of the noble-gas nucleus and the alkali-metal atom, respectively. We have measured the enhancement factor kappa(0) that characterizes these shifts for Rb-Xe-129 to be 493 +/- 31, making use of the previously measured value of kappa(0) for Rb-He-3. This result allows accurate Xe-129 polarimetry with no need to reference a thermal-equilibrium NMR signal.