Abstract
For pt. III see abstr. A64033 of 1971. It is shown that the Born approximation and the sudden-dipole approximation, when applied to the excitation of hydrogenic ions by charged particles, may be cast into the same mathematical form although their regions of validity are complementary. The resulting matrix elements are evaluated using Heisenberg's correspondence principle and the cross sections are obtained in analytic form for a wide range of incident energies. The results for the Born approximation, which are valid for all initial and final states, n and n' such that n>> mod n-n' mod , are compared with available quantal calculations for small n and n' with satisfactory agreement.