Integral cross sections for the electron-impact excitation of the $b$ ${}^1{\Pi }_u$, $c_3$ ${}^1{\Pi }_u$, $o_3$ ${}^1{\Pi }_u$, $b^{\prime }$ ${}^1{\Sigma }_u^{+}$, $c_4^{\prime }$ ${}^1{\Sigma }_u^{+}$, $G$ ${}^3{\Pi }_u$, and $F$ ${}^3{\Pi }_u$ states of N${}_2$

Integral cross sections for electron-impact excitation out of the ground-state level $X{}^1{\Sigma }_g^{+}(v^{\prime \prime }=0)$ to the $b{}^1{\Pi }_u$, $c_3{}^1{\Pi }_u$, $o_3{}^1{\Pi }_u$, $b^{\prime }{}^1{\Sigma }_u^{+}$, $c_4^{\prime }{}^1{\Sigma }_u^{+}$, $G{}^3{\Pi }_u$, and $F{}^3{\Pi }_u$ electronic states in N${}_2$ are reported at incident energies ranging between 17.5 and 100 eV. We also provide excitation cross sections using emission-based excitation shape functions and optical oscillator strengths. These cross-section results are of great importance to planetary atmospheric modeling of the emissions observed in Earth's atmosphere as well as those of Titan and Triton, the largest moons of Saturn and Neptune, respectively. Critical comparisons of the present cross sections with previous values are presented in an effort to provide improved cross sections for electron excitation of this fundamental molecule's important transitions.

Figure 1

Cross sections for electron-impact excitation of the $b{}^1{\Pi }_u$ state in N${}_2$. The legend is displayed in the figure.

Figure 2

Cross sections for electron-impact excitation of the $c_3{}^1{\Pi }_u$ state in N${}_2$. The black dotted curves represent the $b{}^1{\Pi }_u$ shape (1) and the $c_4^{\prime }{}^1{\Sigma }_u^{+}$ shape (2), which are explained in the text. The legend otherwise indicates the plotted data.

Figure 3

Cross sections for electron-impact excitation of the $o_3{}^1{\Pi }_u$ state in N${}_2$. The arbitrarily scaled cross-section shape of Allen et al. [87] is from their measured optical emission cross section for the $o_3{}^1{\Pi }_u$ ($v^{\prime }=0)\to a{}^1{\Pi }_g$ ($v^{\prime }=0$) transition.

Figure 4

Cross sections for electron-impact excitation of the $b^{\prime }{}^1{\Sigma }_u^{+}$ state in N${}_2$. The asterisk (*) in the figure legend brings attention to the present full-ICS estimations ($v^{\prime }$ = 0–16 equivalence) and the present calculated excitation cross section ($v^{\prime }$ = 0–28), which were determined as explained in Sec. IV D. While the thermally averaged CSE-calculated OOS used in normalizing the present calculated cross section is accurate, the collision strength parameters of Ajello et al. [74] are in question, as discussed in the text.

Figure 5

Cross sections for electron-impact excitation of the $c_4^{\prime }{}^1{\Sigma }_u^{+}$ state in N${}_2$.

Figure 6

Cross sections for electron-impact excitation of the $c_4^{\prime }{}^1{\Sigma }_u^{+}$ ($v^{\prime }$ = 0) state in N${}_2$.

Figure 7

ICSs for electron-impact excitation of the $G{}^3{\Pi }_u$ state in N${}_2$.

Figure 8

ICSs for electron-impact excitation of the $F{}^3{\Pi }_u$ state in N${}_2$.