Theoretical calculations of elastic and inelastic scattering of electrons from hydrogen

The electron-hydrogen scattering problem is one of the fundamental problems in atomic physics. Surprisingly, agreement between experiment and even the most sophisticated of theoretical calculations is not good. In this paper, we will discuss our recent attempts at understanding the cause for this disagreement. We have examined the problem both from a perturbation series approach and from the close coupling approach. For the perturbation series method we have calculated exact (no approximations) second order distorted wave amplitudes including second order exchange. For the close coupling method, we have used the optical potential approach and have evaluated the optical potential including the continuum states exactly for the first time. Results will be shown for elastic scattering and for excitation of hydrogen