APPLICATION OF A SIMPLIFIED SECOND BORN APPROXIMATION TO SCATTERING OF ELECTRONS AND PROTONS BY HYDROGEN ATOMS .2.

The simplified second Born approximation is applied to the 1s -> 3s, 1s -> 3p, 2s -> 3s excitations of atomic hydrogen by both electron and proton impact. The excitations from the ground state give total cross sections which behave similarly, with respect to the respective first Born cross sections, to those previously calculated for the 1s -> 2s, 1s -> 2p excitations; they indicate that the first Born total cross sections for optically allowed excitations are reliable over a larger energy range than those for optically forbidden excitations.