ASYMMETRIC THEORIES OF RELATIVISTIC ELECTRON-CAPTURE

New versions of the relativistic continuum-distorted-wave and eikonal models, in their asymmetric form, are presented. These models are char acterized by a two-centre spinor which improves the description of int ermediate scattering through continuum states. It is demonstrated that this is especially important for electron capture with spin-flip. Res ults are compared with experiment and with the conventional scalar dis tortion models. The agreement with experiment is good for total cross sections from inner shells for medium size charges and at GeV amu-1 en ergies. The suitability of the eikonal approximation for spin-flip pro cesses and large momentum transfer is discussed.