Ratios of forward to back scattering of low-energy electrons by neutral gases

Abstract

Measurements are reported on the ratio of forward to back scattering of electrons in the energy range 3-20 eV by He, O, Ar, ${\mathrm{H}}_2$, ${\mathrm{N}}_2$, and ${\mathrm{O}}_2$ using the modulated crossed-beam technique. It is found that atomic oxygen has strong forward scattering at the lower energies. Agreement is found between the present results for He, Ar, ${\mathrm{H}}_2$, and ${\mathrm{N}}_2$ and ratios calculated from previously published differential-cross-section measurements except for ${\mathrm{H}}_2$ and ${\mathrm{N}}_2$ at the lower-energy limit.