tion by He2+ impact at energies between v=0.6 to 2 a.u. ... superpromotion theory assumes that electrons are promoted ... orbitals is frequently used in the study of atomic collision .... states of the projectile to ionization cross section cannot be e. VTry)=-= -( 1 +0.4143rT)-. IT. (6). YT ... with each other reasonably well.