Origin of the Characteristic Electron Energy Losses in Magnesium

The characteristic electron energy loss spectrum of magnesium has been measured by analyzing the energy distribution of 750-, 1000-, 1505-, and 2020-ev electrons scattered by an evaporated specimen through 90^. The spectra were similar in form to those previously obtained with aluminum targets, in that the observed loss peaks were composed entirely of combinations of two elementary energy losses. These two losses, of magnitude 7. 1 and 10. 6 ev, were identified, respectively, with the lowered plasma loss proposed by Ritchie and the plasma loss proposed by Bohm and Pines.