Some Effects of Collisions on the Fluorescent Radiation from a J=1 and a F=3/2 Multiplet.

When a pulsed excitation is used to prepare an atomic system in a coherent superposition of excited substates and the subsequent fluorescence is observed with the proper polarizations, oscillations called quantum beats are seen in the radiation. The effects of collisions between the radiating atom and other atoms on this fluorescence are studied. A general expression for the radiation intensity including collisional effects is derived and applied to a j = 1 Zeeman triplet and a f = 3/2, 1/2 hyperfine multiplet. In doing the hyperfine calculation a major result of the theory was the transfer of coherence caused by these collisions from one part of the multiplet to another part.