Relativistic effects in electron-atom collisions

Relativistic effects in electron-atom collision cross sections are discussed. According to the results obtained using the relativistic distorted-wave Born approximation, relativistic cross sections for electron-impact excitations of Li-like ions are smaller than corresponding nonrelativistic cross sections. This reduction results mostly relativistic contraction of bound orbitals and from spin-orbit splitting. We also found that electron exchange and orthogonality between bound and continuum orbitals did not significantly alter cross sections for highly charged ions.