A SEMICLASSICAL APPROACH TO THE CALCULATION OF ELECTRON-IMPACT IONIZATION CROSS-SECTIONS OF ATOMS - FROM HYDROGEN TO URANIUM

Absolute ionization cross-sections for single ionization by electron impact (from threshold up to 200 eV) of free gaseous atoms have been calculated by utilizing a recently proposed semiclassical approach (DM formulation). The formula used here is derived within the framework of classical and quantum mechanical approximations, and the necessary input parameters are determined and discussed. Where possible the calculated ionization cross-section functions are compared with experimental data sets and with the most widely used previous formulae such as the Gryzinski and Lotz formulae. It is concluded that the present approach leads on average to a better agreement with experimental results than previous classical, semiclassical and empirical treatments.