Electron impact excitation of 2p and 3p states of hydrogen at intermediate energies

The recent theoretical work by Bartlett et al. [J. Phys. B 38, L95 (2005)] and the latest measurements on the reduced Stokes parameters $\overline{P}_1$, $\overline{P}_2$ and $\overline{P}_3$ for 54.4 eV electron impact excitation of the 2p state atomic hydrogen by Williams and Mikosza [J. Phys. B 39, 4113 (2006)] has motivated the present work. A coupled-channel-optical calculation with 9 and 12 atomic states supplemented with the continuum optical potentials for the stronger coupling channels has been performed. The calculated n = 2 and n = 3 differential cross sections and the reduced Stokes parameters are comparable with the state-of-the art calculations. There is closer agreement between the present calculations and the experimental measurements for the reduced Stokes parameters $\bar {P}_1$ and $\bar {P}_3$ in the n = 2p excitation at 54.4 eV. The present CCO calculations also display good accord with the limited experimental data for the reduced Stokes parameters in the n=3p excitation