Differential Electron Scattering from Fundamental Atoms and Molecules

A brief survey of recent work, in our laboratory, on the differential scattering of low energy electrons from H, He, H$_{2}$ and N$_{2}$ will be presented. This work includes accurate measurements of doubly-differential ionization cross-sections for electron impact ionization of H using a novel moveable source method [1] and an extension of this to the electron impact single ionization of He [2]. We will also present ongoing work in electron-molecule collisions, and discuss recent observations on interference effects in the electron impact, vibrational excitation, of N$_{2}$ Rydberg states [3] and the resulting break-down of the Franck-Condon principle. \newline \newline This work is supported by a grant from the National Science Foundation under the RUI Program. \newline \newline References: \newline [1] M. Hughes et al., Meas. Sci. Technol. \underline {14}, 841 (2003). \newline [2] E. Schow et al., Contributed Poster, DAMOP 2005. \newline [3] B. R. Lewis et al., Phys. Rev. A, 2005 in press.