Measurements of differential cross sections for elastic electron scattering in the backward direction by molecular oxygen

Absolute differential cross sections have been measured for elastic electron scattering by molecular oxygen in the backward direction over the scattering-angle range 100°–180°, at selected incident energies in the range 7–20 eV. These measurements employed the magnetic angle-changing technique with a newly designed conical-solenoid source for the localized magnetic field. The measured differential cross sections are presented together with previous experimental work and the results of theoretical calculations. Integrated elastic and momentum transfer cross sections have been deduced using the measured differential cross sections for backward scattering together with existing differential cross sections for forward scattering.