Ionization of metastable H(2 S) atom by electron and positron impact.

Triple differential cross-section (TDCS) of hydrogen atom in its metastable (2 S) state is studied theoretically by electron and positron impact for coplanar and asymmetric geometry. The final-state wave function in the present model satisfies the asymptotic boundary condition for asymmetric geometry ( i.e. for k ≫ k ). In the absence of experiment, present results are compared with other existing theoretical results. Apart from the double-peaked structure of the TDCS as in ground-state ionization, some interesting secondary structures are found, in conformity with other theories for ionization from 2 S state. [ABSTRACT FROM AUTHOR]