Production of electronically excited ${\mathrm{N}}_2^{+}$ ions by electron impact on ${\mathrm{N}}_2$ molecules

Measurements of the optical emission cross sections for the ${\mathrm{N}}_2^{+}$ ${\mathit{D}}^2$ ${\mathrm{\Pi }}_{\mathit{g}}$→A ${}_{}{}^2{}_{}{}^{}\mathrm{\Pi }_{\mathit{u}}^{}{}_{}{}^{}$ emission bands produced by electron impact on ${\mathrm{N}}_2$ are reported. From these optical data, estimates of the apparent cross sections for the electron-impact production of ${\mathrm{N}}_2^{+}$ (D ${}_{}{}^2{}_{}{}^{}\mathrm{\Pi }_{\mathit{g}}^{}{}_{}{}^{}$) in the vibrational states v=4, 7, and 9 are obtained. Combining these data with similar cross sections for the ${}_{}{}^2{}_{}{}^{}\mathrm{\Pi }_{\mathrm{u}}^{}{}_{}{}^{}$→X ${}_{}{}^2{}_{}{}^{}\mathrm{\Sigma }_{\mathrm{g}}^{+}{}_{}{}^{}$ and ${}_{}{}^2{}_{}{}^{}\mathrm{\Sigma }_{\mathrm{u}}^{+}{}_{}{}^{}$→X ${}_{}{}^2{}_{}{}^{}\mathrm{\Sigma }_{\mathrm{g}}^{+}{}_{}{}^{}$ bands and with ionization cross sections of ${\mathrm{N}}_2$ enables us to analyze the systematics of the cross sections for producing ${\mathrm{N}}_2^{+}$ in the X ${}_{}{}^2{}_{}{}^{}\mathrm{\Sigma }_{\mathrm{g}}^{+}{}_{}{}^{}$, A ${}_{}{}^2{}_{}{}^{}\mathrm{\Pi }_{\mathrm{u}}^{}{}_{}{}^{}$, ${}_{}{}^2{}_{}{}^{}\mathrm{\Sigma }_{\mathrm{u}}^{+}{}_{}{}^{}$, and D ${}_{}{}^2{}_{}{}^{}\mathrm{\Pi }_{\mathrm{g}}^{}{}_{}{}^{}$ states. Two different kinds of excitation behaviors are found and are discussed in reference to the electronic structure of the ${\mathrm{N}}_2^{+}$ ion.