Experimental determination of orbital and spin orientation of (Ar+)* formed in collisions

We have experimentally obtained the state multipoles up to rank two for J-resolved 2F7/2,5/2 states of Ar+ for the two-electron process He++Ar→He(1s2)+Ar+(3p4[1D]4p2Fo7/2,5/2) by measuring the Stokes parameters of the fluorescence light from (Ar+)* in coincidence with the scattered He. By expanding the state multipoles of each J state in terms of total orbital and total spin multipole moments, we have determined the contributions to the experimentally determined state multipoles of each J state due to total orbital and total spin angular momenta. When the process is spin dependent, it is possible to extract magnetic octupole moments of the excited state due to the orbital charge circulation. copyright 1996 The American Physical Society