Direct excitation near the thresholds for alkali-like ions impacted by electrons

A new method is described for solving the multi-channel equation, in which channel wave functions are expressed in terms of the homogeneous solutions analytically. By using the method, direct excitations of Mg+, Be+, Ca+, Cd+ and Ba+ ions impacted by electrons are calculated for the energies close to their thresholds. The calculated results are compared with the experimental results and previous theoretical calculations. The lack of orthogonality between the channel wave functions and the orbital wave functions of the target ions is considered.