Initial- and final-state alignment and orientation effects in Ca energy pooling

An experimental investigation is performed to determine the initial- and fi nal-state alignment effects in the energy-pooling process Ca(4s4p P-3(1)) Ca(4s4p P-3(1))-->Ca(4s4p P-1(1)) + Ca(4s(2)). This paper represents a typ e of four-vector correlation experiment, where two aligned atoms collide an d the alignment of the final excited state is observed. The initial Ca(4s4p P-3(1)) state polarization is controlled with polarized lasers and magneti c fields, and the final-state alignment is partially resolved by observing the polarization of the fluorescence from the Ca(4s4p P-1(1))-->Ca(4s(2)) e mission. The mathematics are developed in this paper to provide a full quan titative description of the four-vector alignment cross sections observed h ere. Relative values that describe 18 of the 39 total independent parameter s are obtained, thus defining the results of this collision process at an u nprecedented level of detail. The final-state Ca polarization is found to b e only weakly dependent on the initial-state alignment, with final-state fl uorescence predominately polarized along the relative velocity vector of th e collision. [S1050-2947(99)00510-7].