Collisions of fast electrons with helium. III. Excitation of the (1s, nd)1D and (ns, mp)1P states

For pt. II see abstr. A56132 of 1972. A simplified second Born approximation together with a third order approximation has been used to calculate differential and total cross sections for the electron excitation of the 32D and 42D states of hydrogen, the 31D and 41D of helium, and of model doubly excited states of helium. Where possible, comparisons with experimental data are made. Large corrections occur to the first Born cross sections for the excitation of the model doubly excited states and it is suggested that these corrections may also be expected to the first Born results for simultaneous excitation and ionization.