Relativistic effects exhibited by the generalized Stokes parameters for electron impact excitation of quasi one-electron atoms

Abstract

The generalized Stokes parameters are an extension of the regular Stokes parameters by considering spin-polarized incident electrons. We have derived relationships between the generalized Stokes parameters in the non-relativistic fine-structure approximation. Relativistic effects in the intermediate energy range are due to spin - orbit coupling. These effects are masked when averaging over the electron spin polarization for the regular Stokes parameters, but are very prominent for the generalized Stokes parameters. We have considered quasi one-electron atoms and have found that Rb, Cs, Cu, Ag and Au exhibit strong relativistic effects, while K shows weaker effects and Na almost none at all. The experimental testing of these effects can complement those which are exhibited by the generalized STU parameters.