Electron-impact excitation of molecular nitrogen. II. Vibrationally resolved excitation of theCΠu3(v′)state

Electron impact study of the 100 eV emission cross section and lifetime of the Lyman‐Birge‐Hopfield band system of N2: Direct excitation and cascade

“…Previously, Meier [] and Ajello et al [] have reviewed the combined effect of N 2 * cascades from the a ′ 1 Σ − u and w 1 Δ u states by electron impact using the results of Cartwright [] and showed that their contribution to the LBH emission can be significant (>25%). It should be noted that the excitation cross sections used by Cartwright [] are based on the integral cross sections of Cartwright et al [], which are based on the underlying energy‐loss‐derived differential cross sections of Cartwright et al [], and are largely estimated interpolations (and extrapolations) of sparse experimental data points that depended on assumed Franck‐Condon (FC) behavior even near to threshold (note that FC behavior has been shown to deviate at lower impact energies [see Khakoo et al , ; Malone et al , , , , ]). Consequently, the results of Cartwright [] should be used with caution.…”

N2(A) in the Terrestrial Thermosphere

“…Similarly, Figure shows that the effective N 2 (a) state cross section (i.e., the summed J 05 M 09 singlet excitation cross sections) is smaller at all energies but converges to those of T 83 above about 30 eV. See Section 4 of Malone, Johnson, Kanik, et al () and Section 3 of Malone et al (), for a discussion of how the shape functions of the older Cartwright et al cross sections do not always pass directly through the data points and are extrapolated at low energies. Also, it must be mentioned that the electron energy loss unfolding of Cartwright et al did not include the w state below 12.5 eV nor the a ′ state below 15 eV.…”

“…As shown in Figure and the appendix, the most recent laboratory determinations of the N 2 triplet (A, B, W, B ′ , and C) integral excitation cross sections (Johnson et al, and Malone, Johnson, Kanik, et al, , referred to collectively as J 05 M 09] are generally lower in magnitude and have more complex shapes than those used by the aeronomy community for much of the past thirty years (Broadfoot et al, ; Cartwright, Trajmar, et al, ; Trajmar et al, ). Similarly, Figure shows that the effective N 2 (a) state cross section (i.e., the summed J 05 M 09 singlet excitation cross sections) is smaller at all energies but converges to those of T 83 above about 30 eV.…”

“…Based on the somewhat larger measurements of Campbell et al (), Itikawa () recommends 35% uncertainty in the cross sections for the A, B, C, and W states. This recommendation does not, however, include the significantly lower measurements of Johnson et al () and Malone, Johnson, Kanik, et al (). These latter two measurements will be collectively referred to as J 05 M 09.…”

Tuning out vibrational levels in molecular electron energy-loss spectra

“…u states as independent features, rather than using Franck-Condon factors to fix their relative intensities, similar to our approach in a number of recent works [10,19,20]. A nonlinear least-squares algorithm was used to fit the features in each multi-channel spectrum in the energy-loss region of interest, with a line shape determined empirically by the separate fitting of a multi-Gaussian function to the isolated a (0) feature.…”