ALIGNMENT OF MG-IMPACT IONIZATION IN THE RANGE FROM NEAR-THRESHOLD TO300 EV((L3) IONS AFTER ELECTRON)

The alignment A20 of Mg+(L3) ions after electron impact ionization has been measured for the range of impact energy E0 = 300 eV down to 59.8 eV; the latter value is close to the threshold energy E(L3) = 57.54 e V. The experimental alignment values agree reasonably with the results of a BA calculation for E0 > 100 eV but disagree with DWBA results in the full range of energy. From the alignment value obtained near thre shold, A20 = -0.18(5), it is concluded that two-electron partial waves with L = 0 and L > 0 contribute to the Wannier threshold cross sectio n.