FIELD-DEPENDENCE OF SPIN RELAXATION IN A DENSE RB VAPOR

We observe that the Rb-Rb relaxation rate for spin polarized Rb is red uced by a factor of 3 in magnetic fields of a few kG, even at multiatm osphere buffer gas pressures. This reduction is proportional to the Rb density and is independent of buffer gas pressure between 100 and 300 0 Torr. We also report anomalously large relaxation rates below 100 To rr. Both of these observations are inconsistent with the previously he ld assumption that the Rb-Rb relaxation arises from sudden binary coll isions.