Angular-momentum transfer in collisional ionization.

Abstract

The double-differential cross sections for ionization in [ital e][sup [minus]]+H([ital nl]) collisions are reported as a function of the impact energy [ital E] of the projectile, final energy [ital E][sub [ital f]], and angular momentum [ital L][sub [ital f]] of the ejected electron. This process is assumed to occur via an energy-changing and angular-momentum-changing binary collision between the Rydberg electron in a prepared state ([ital nl]) and the projectile electron [ital e][sup [minus]] or H(1[ital s]). The atomic projectile can also be excited during this process. Systematic trends in the variation of the classical ionization cross sections with final angular momentum [ital L][sub [ital f]] of the ejected electron are discussed and are in accord with a previous quantal treatment, whereby the nondipole ([Delta][ital l][gt]1) transitions are much more important in the low- and intermediate-energy range of relative motion, and that the value of the final angular momentum of the ejected electron depends mainly on the initial value of the principal quantum number [ital n] of the Rydberg atom.