Abstract: Cross section for the excitation of Al¹⁰⁺ ion by electron impact from ground state to 2p,3s and 3p states has been investigated with 2-state does-coupling (2cc) and 5-state close -coupling(5cc) approximations. The indirect coupling effect has been analyzed, comparing with the results of distorted wave approximation, it is found that the coupling effect is less important for 2s-2p transition, but for 2s-3s and 2s-3p transition it should be taken into account.

Key words: close-coupling, excitation, cross section