POLARIZATION STUDIES OF RARE-GAS RESONANCE RADIATION - ARGON, KRYPTON, AND XENON

The linear polarization of resonance vacuum-ultraviolet (VUV) radiatio n emitted by electron-impact excited Ar, Kr, and Xe atoms has been mea sured in the energy range from threshold to 480 eV using two sets of a pparatus. The first apparatus measured the polarization function in th e near-threshold region using an energy selected electron beam with a resolution of 160 meV. This enabled the effects of negative-ion resona nces on the polarization function to be examined in detail. Prediction s of the effects of negative-ion resonances on the observed polarizati ons have been made using a generalized Baranger-Gerjuoy theory. Excita tion via electron exchange is shown to be a significant process very c lose to threshold. The second apparatus used an electron beam with sim ilar to 1 eV resolution to probe the broad features of the VUV polariz ation functions over the energy range from threshold to 480 eV. Measur ements are compared with other published data.