Studying the state multipoles of excited atoms and ions by measuring the polarization of light emitted from the excited states is important in atomic physics. Such work yields information about:

• The effect of the spin dependence in ionization and/or excitation collisions


• Anisotropy and geometry of the excited states


• Collision mechanisms and electron correlation


• The density matrix of the system

There have been many related experiments. However, none of them has reported a measurement of a rank 6 multipole.

• (e,2e) measurement on Kr
  1 .P. A. Hayes et al. J. Phys. B 31, L193 (1998)


• coincidence measurements of scattered He+ and a photon emitted from the excited Ar. The present experiment produced complement this experiment.
  2 .W. Moudry et al. Phys. Rev. A 54, 4119 (1993)


• measuring flourescence polarization from several fine structure states excited by synchotron radiation
  3 .O. Yenen. et al. Can J. Phys. 74, 955(1996)