Excitation from the ground state of helium to higher¹S states

Cross sections for excitation of 1 S states are calculated in the Born approximation. For the 1 1 S-2 1 S differential cross section a variety of wave functions are used. For 1 1 S- n 1 S total cross sections, n = 2... 10, a self-consistent field function is used for the ground state and a truncated Whittaker function, orthogonalized to the ground state function, is used for the excited states. The theoretical results are compared with those obtained experimentally.