Angular momentum partitioning and hexacontatetrapole moments in impulsively excited argon ions.

We have studied polarized electron collisions with Ar in which the target is simultaneously ionized and excited to form Ar+(3p(4)(1D)4p) states. We measured the integrated Stokes parameters of the subsequent fluorescence emitted by the (2)F(7/2), (2)F(5/2), (2)D(5/2), and (2)P(3/2) states along the direction of electron polarization. The Rubin-Bederson hypothesis is shown to hold for the L and S multipoles of these states. The electric quadrupole and hexadecapole of the 1D core are derived. By recoupling these moments with the electric quadrupole moment of the 4p electron, we calculate higher moments of the total ionic orbital angular momentum, including its hexacontatetrapole (64-pole) moment.