INVESTIGATION OF SPIN-ORBIT EFFECTS IN THE EXCITATION OF NOBLE-GASES BY SPIN-POLARIZED ELECTRONS

We have measured the integrated Stokes parameters of the light emitted following the impact excitation by polarized electrons of the np5 (n1)p[5/2]3 states in Ne (n = 2), Ar (n = 3), Kr (n = 4), Xe (n = 5), an d the np5 (n+1)p [5/2]2 state in Kr. The near-threshold linear-polariz ation fractions eta1 were consistent with zero for all of the J = 3 st ates measured, providing no evidence of Mott scattering. For J = 2 exc itation, eta1, shows the clear influence of the intermediately coupled nature of the state. At threshold, the measured circular polarization eta2 and linear polarization eta3 for the J = 3 states agree well wit h the LS-coupled threshold predictions. These results provide the basi s for optical measurements of electron polarization.