SIMPLE-MODELS FOR THE CALCULATION OF PHOTOIONIZATION AND ELECTRON-IMPACT IONIZATION CROSS-SECTIONS OF POLYATOMIC-MOLECULES

In this paper two semi-empirical models are presented. By the one mode l the electron impact ionization cross sections of polyatomic molecule s can be estimated for electron energies in the range from 15 to 150 e V. Using the other model the photoionization cross section of polyatom ic molecules is determined at photon energies of 11.8 and 16.7 eV. In the case of electron impact, the model reproduces the molecular ioniza tion cross sections within 20% at electron energies above 50 eV. The p hotoionization cross sections calculated with the model deviate not mo re than 20% from the experimentally determined values for all polyatom ic molecules tested.