Direct and indirect relativistic effect on electron scattering from cesiumand gold atoms

The differential cross section (DCS), Stokes parameters, and the STU parame ters for electron scattering from a cesium atom are calculated by two kinds of distorted-wave methods, each including different relativistic effects. Comparing our results with those from the relativistic distorted-wave metho d of the Toronto group, we find that, at an incident electron energy of 50 eV, the direct relativistic effect is more important than the indirect rela tivistic effect for cesium. Further the direct relativistic effect leads to the invalidity of the "fine-structure approximation'' for the case of cesi um. We also calculated the DCS and the Stokes parameters for an electron-go ld collision at incident electron energy of 50 eV. Unlike the cesium case, the indirect relativistic effect is more important for gold.