“…Atoms in metastable states possess certain characteristic properties, such as long lifetimes, capability of transferring large amounts of energy [1], low excitation and ionization potentials, leading to extremely large scattering cross-sections. From this point of view, electron impact ionization of metastable atoms is finding potential importance for understanding of mechanisms occurring in many research areas, e.g., astrophysics, plasma physics and also in life sciences.…”