A modification of the Brinkman-Kramers approximation incorporating Coulomb distortions

A modification has been made to the Brinkman-Kramers approximation on the basis of the distorted-wave method, which enables one to represent the electron-capture cross section as the product of the BKA cross section and the coefficients $\alpha$ and $\beta$ describing the distortion of the electron wave functions due to interaction with the target atom in the exit channel and with the incident ion in the ingoing channel correspondingly. It is shown to be important to incorporate the distortions in the two channels at low and medium energies.