Near-threshold electron-impact excitation cross section for the EΣg+3state ofN2

The electron excitation function for the metastable states of molecular nitrogen has been analyzed to reveal the excitation cross section for the E ${}_{}{}^3{}_{}{}^{}$ ${\mathrm{\Sigma }}_{\mathrm{g}}^{+}$ metastable state of ${\mathrm{N}}_2$. This cross section has been placed on an absolute scale by a normalization technique based on the argon metastable-atom excitation cross section. The resultant cross section is dominated near threshold by a strong, narrow negative-ion resonance. The general features of the near-threshold cross sections are entirely consistent with a number of recent excitation functions for the E state but not with previously published absolute values.