Relativistic calculation of scattering parameters for superelastic electron-atom collisions

Superelastic electron-atom scattering experiments are often more desirable to perform than inelastic experiments, in part due to the ability to excite specific fine-structure (and hyperfine-structure) states with relative ease. The superelastic scattering parameters measured, however, are often compared with inelastic parameters which have been measured or calculated by other groups, even though the two cases are not exactly the time-reverse of each other (inelastic experiments cannot resolve hyperfine-structure states). To do this there must exist a theoretical framework by which the various parameters for the two cases can be compared. In the non-relativistic limit a general framework has been developed for n'p → ns transitions in quasi one-electron atoms. The authors extend these calculations to the relativistic case where jj-coupling, rather than LS-coupling, is employed. Examples of calculations using the relativistic distorted-wave approximation will be given