Electron impact excitation of the n¹P(n=2-5) and 2³P states of helium at intermediate energies

Calculations are reported on the electron impact excitation of the n1P (n=2,3,4,5) states of He from the ground state. The incident energy range covered is from threshold to 500 eV, and the calculations are carried out in the distorted-wave polarized-orbital model. Total cross sections for all n<or=5, total differential cross sections differential cross sections for individual magnetic sub-levels, and orientation and alignment parameters for n=2,3 are presented and compared with other theoretical studies and with experiment. Excitation of He (23P) is briefly discussed.