Excitation and ionization of neutral atoms in a dense discharge

Closed forms for the electron-impact cross sections are used to evaluate excitation and ionization rates of the ground state of some atoms currently used in discharge physics. A Maxwellian and a Druyvesten distribution are considered respectively for the electron distribution velocity. Excitation processes are seen to be much more dependent on the atomic structure and the electron distribution than on ionization. Conversely, the latter process is much more sensitive to the electron temperature. Estimates of the electron density for the existence of complete local thermodynamic equilibrium are also discussed.