Angular distributions for the electron impact excitation of the n=2 levels of atomic hydrogen

Differential cross sections and the electron-photon correlation parameters lambda and R have been calculated for electron impact excitation of the n=2 states of atomic hydrogen at energies of 54.4 and 35 eV. All calculations were carried out within the conventional close-coupling approximation. The effects of exchange and of the inclusion of pseudostates in the target state basis were investigated. Improved agreement with experiment for the parameter lambda was obtained at both energies.