Angular momentum transfer and polarization degree of ions with one-valence electron by electron impact

We carry out the R-matrix calculations for electron-impact excitations of ions with one valence electron. The integral cross sections and polarization degree are obtained for the excitation process from the ground state to the first 2P0 state of Li2+, B2+ and Al2+ as functions of electron incident energy. The differential cross sections and angular momentum transfer are also shown at non-resonant low-energy points. As for the angular momentum transfer (Lperpendicular) at small scattering angles, they are negative for B2+ and Al2+, while it is positive for Li2+. Thus Lperpendicular of doubly charged ions with one-valence electron is not simple.