EFFECT OF Na-Na SPIN-EXCHANGE COLLISIONS ON SPIN RELAXATION OF OPTICALLY PUMPED Na IN Xe GAS

We report the first detection of the effect of Na-Na spin exchange collisions on spin relaxation of optically pumped Na in Xe gas by studying the relaxation in the 'dark" of the variable < S_Z > in a mixture of dense sodium vapor (number density Na~10¹³ cm^-3) , and buffer gas helium, xenon and nitrogen as a function of Na and xenon pressure.