“…Our present study is on the ionization of metastable 3Sstate hydrogen atoms by 250 eV incident energy triple H (3S) by Electron Impact differential cross-sections (TDCS) has been calculated following a multiple scattering theory of Das and Seal [11]. Using this multiple scattering theory [11] good cross sectional results for the ground state hydrogenic ionization [11,13] and hydrogenic metastable state ionization [22,23,40,41] by electrons have been calculated successfully. This multiple scattering theory [11] is also used widely in the study of medium-heavy atoms ionization by electrons and positrons in the relativistic energy region [17,24,35,36].…”