Electron-loss cross sections of lithium atoms in gases

Electron-loss cross sections sigma 01 for ground-state lithium atoms traversing hydrogen, helium, nitrogen, neon, argon, krypton, and xenon within the range of impact energies from 20 to 500 keV have been measured by beam attenuation in a transverse electrostatic field. These experimental cross sections for loss of the loosely bound valence electron in neutral lithium are compared with the theoretical estimates, based upon the semi-empirical classical impulse approximation of Bates and Walker (1966). Further, the present cross sections for lithium atoms are compared with published experimental electron-loss cross sections for metastable hydrogen and helium atoms. On the basis of the theory mentioned above, similarities between these cross sections are expected. The overall agreement between the cross sections presented and the theoretical estimates, as well as the experimental electron-loss sections for metastable hydrogen and helium atoms is reasonable. A more detailed comparison is, however, made difficult by the fact that results from different laboratories in some cases show poor agreement.