Anisotropic Spin-Exchange

Abstract

Using measured spin-transfer rates from alkali atoms to 3He, combined with spin-relaxation rates of the alkali atoms due to 3He and 4He, it should be possible to di?erentiate between isotropic and anisotropic spin-exchange. This would give a fundamental limit on the 3 He polarization attainable in spin-exchange optical pumping. For K-He, we ?nd the limit to be 0.90?0.11.