Absolute total electron scattering cross sections for ${\mathrm{N}}_2$ from 0.5 to 50 eV have been measured with an estimated uncertainty of ±3% using a transmission time-of-flight method previously described. The results are compared to previous experimental results and to recent calculations. The positions of the ${}_{}{}^2{}_{}{}^{}\Pi _g^{}{}_{}{}^{}$ resonance peaks were determined with much greater accuracy (± 15 meV) than in previous transmission measurements. The structure reported by Golden (1966) below the ${}_{}{}^2{}_{}{}^{}\Pi _g^{}{}_{}{}^{}$ resonance was clearly not present, indicating that, if real, these features are not a property of the ${\mathrm{N}}_2$ ground vibronic state. The shape resonance predicted at 11 eV by Dill and Dehmer (1977) was not seen, perhaps because it was too weakly manifested in the total cross section. A weak broad band centered at 25 eV may be interpreted as being due to a ${\sigma }_u$ shape resonance as predicted by Dehmer, Siegel, Welch, and Dill.

• Received 6 December 1979

DOI:https://doi.org/10.1103/PhysRevA.21.1876