The energy dependence of relativistic nonradiative electron capture
  The energy dependence of the nonradiative electron capture cross-section is discussed in the relativistic domain. A simple analytic expression is obtained for inner-shell transitions using second-order perturbation theory. We have confirmed that the leading-order term is found to have the following energy dependence: Q ~ E^{-1}ln^2 E. This is attributed to a combination of kinematic features of the process and retardation effects. Electron capture without change of spin is the dominant transition. 
J F McCann (1), J T Glass (2) and D S F Crothers (2) ((1) Department   of Physics, University of Durham, Durham, England, (2...