ELECTRON-IMPACT IONIZATION OF LITHIUM CLOSE TO THRESHOLD

The triple differential cross section for e-Li has been calculated in a distorted-wave approximation at incident energies in the range 0.5 to 20 eV above the ionization threshold in the coplanar theta(ab) = 180 degrees and perpendicular geometries and equal energy sharing situation. The results are compared with those for hydrogen. The variations in the two cases are found to be qualitatively very different. It is found that, in the case of lithium, the D and F partial waves in the final state are quite significant except when the excess energy is less than about 0.5 eV.