Charge-Stripping Processes of Hydrogen-Like Ions by Collisions with Neutral Hydrogen Atoms

The cross sections for the processes: A (z A -1)+ (1s)+H(1s)→A z A + +e+H, were calculated in the classical binary-encounter approximation (BEA,), where the H + and e in H are assumed to separately collide with the ion, and in the plane-wave Born approximation (PWBA), where the contributions due to the stripping reactions by H + and e in the scattering amplitude.are superposed. The cross sections are evaluated for the processes which produce H(1s)(σ A ) and those which produce excited and ionized H(σ A ) in the final state. For ions with Z A ≥6, the BEA total cross sections, scaled with respect to Z A , agree with those (σ A +σ B ) calculated in the PWBA to within a factor of 1.1 at relative velocities less than 1.5 a.u. and within a factor of 1.5 up to 10 a.u. In the PWBA approximation, the average excitation energy for atomic hydrogen is introduced in order to evaluate σ B , while the cross section becomes independent of this energy at sufficiently high incident energies. In the BEA, such an average excitation energy is unnecessary.