PRINCIPAL QUANTUM NUMBER DEPENDENCE FOR ELECTRON-HYDROGEN COLLISIONS

Over the last two decades, there has been considerable interest in the electron-atom scattering problem. Most of this work has concentrated on elastic scattering and excitation of the lowest energy states. Howe ver, due to recent technological advances, it is now becoming possible to examine experimentally the excitation of higher lying states. The important question then concerns whether these higher states contain n ew information. It has been argued that the scattering amplitudes for electron-helium excitation should scale with principal quantum and thu s contain no new information. The purpose of this work is to examine t he n-dependence for electron-hydrogen scattering. The converged-close- coupling and second-order distorted-wave methods have been used to cal culate scattering amplitudes for excitation of the n = 2, 3 and 4 leve ls of the hydrogen atom. The n-dependence of the integrated cross sect ions, differential cross sections and angular correlation parameters w ill be discussed for energies from threshold to 500 eV.