Electron-impact excitation of H and He

The method suggested by Crothers and McCarroll (Proc. Phys. Soc., 86:753 (1965)) for the study of electron-impact excitation of neutral atoms has been used to calculate the differential and total excitation cross section in hydrogen and helium. Transitions from the ground state to ns, np and nd (n >= 3) in hydrogen and to m 1P states (m = 2 and 3) in helium have been considered. Highly accurate wavefunctions of Hartree-Fock type as well as approximate but simple wavefunctions due to Messmer (Theor. Chem. Acta.; 14:319 (1969)) have been employed respectively for the ground and excited states of helium. The results of the present calculations are compared with the other available theoretical and experimental results. (author)