Total Electron Scattering Cross Sections inO2and Ne

Abstract

A modified Ramsauer technique has been used to measure the total low-energy scattering cross sections of electrons in ${\mathrm{O}}_{2}$ over an energy range from 2.35 to 21 eV, and in Ne over a range from 0.37 to 20 eV. A broad clearly defined bump is observed in the $e\ensuremath{-}{\mathrm{O}}_{2}$ cross section with the maximum occurring between 11 and 12 eV. Both the ${\mathrm{O}}_{2}$ and Ne cross-section data are in good agreement with Br\uche's measurements at energies above 2 eV. Extrapolation of the low-energy Ne data to zero energy, using modified effective-range theory, yields a zero-energy scattering length of $(0.30\ifmmode\pm\else\textpm\fi{}0.03){a}_{0}$, where ${a}_{0}$ is the Bohr radius.