Abstract: The problem of the slow convergence has been resolved in partial wave expansion for the excitations of electron-ion collisions, with three approximations including plane wave, coulomb Bethe and equimultiple decrease series. As an example, we have computed some important transitions of Ne-like Ge ion and made comparisons between the results obtained by three approximations. The results slow-that all the three methods are acceptable.

Key words: partial wave convergence, plane wave, coulomb Bethe, equimultiple decrease series