Born cross sections for the electron and proton excitation of helium calculated using unrestricted Hartree-Fock wave functions

Abstract

Unrestricted Hartree-Fock wave functions are obtained for the n 1S (n = 1 to 6), n 1P (n = 2 to 6) and n 1D (n = 3 to 6) states of atomic helium. They are used to calculate the first Born approximation cross sections for electron and proton excitation of the ground state of helium to these states. Calculations are carried out using both the length and velocity formulations of the Born approximation integrals and comparison with accurate values shows that these wave functions yield entirely satisfactory results for excitation of n 1S and n 1P states, but are unsatisfactory for excitation of n 1D states.