The results of laboratory experimental measurements relevant to iodine Hall effect thrusters are presented. Specifically, emission excitation cross sections determined from three separate collision systems are presented. Cross sections are determined from collision of electrons with molecular iodine (I_2) over an electron energy range of 4-100 eV along with collisions of atomic iodine cations (I~+) with I_2 and molecular iodine cations (I_2~+) with I_2 over an energy range spanning 4-400 eV in the center-of-mass collision frame. The results are interpreted with respect to the formulation of a collisional radiative model (CRM) that can be applied to the plume of an iodine ion thruster to determine the local electron temperature. The presented results indicate that the emissions from atomic lines generated from population in the 6p electronic state cannot be used to formulate the CRM. The energy dependence of the cross section for the various 6p upper states appears unchanged relative to one another in all reactions studied. The results are discussed with respect to implications to the thruster plumes.
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