Experimental study of cesium 5D 5D→6S (nL=9D,11S,7F)energy pooling collisions

We report experimentally the measured rate coefficients for the energy pooling(EP)collisions process Cs(5D) Cs(5D)→Cs(6S) Cs(nL=9D,11S,7F)in cesium densities of 10~(16)-10~(17)cm~(-3).The 5D state was populated via 8S→7P→5D spontaneous emission following two-step pumping 6S→6P_(3/2)→8S. Since the 5D→6P(3.0—3.6μm)fluorescence could not be detected in this experiment,we carried out a relative measurement for the process 6P 5D→6S 7D.The excited-atom density and spatial distribution were mapped by monitoring the absorption of a counterpropagating single-mode laser beam, tuned to 6P_(3/2)→9S_(1/2)transition,which could be translated parallelly to the pump beam.The excited atom densities have been combined with the measured fluorescence ratios to yield EP rate coefficients. The average values for nL=9D,11S and 7F are 8.0±4.0,7.0±3.5,and 9.3±4.6(in units of 10~(-10) cm~3/s),respectively.Influence of the energy transfer process 11S 6S(?)7F 6S on the rate coefficients k_(11S)and k_(7F)is also discussed.