Theoretical study of the n=2 excitation of atomic hydrogen by proton impact

The n=2 excitation of atomic hydrogen by proton impact has been studied using the semiclassical impact parameter coupled-channel method in the range of impact energies between 15 and 1000 keV. In the discussion that follows, special attention is paid to the interval from 15 to 200 keV where theoretical cross sections show considerable variation depending on the particular choice of the expansion basis and where experimental data for excitation of the 2p subshell have recently become available.