Emission frequency, , of each neutral species and emission line: (a) OI1356, (b) OI3014, (c) Ly-β and OI1027, (d) CI1657 and CO4PG, and (e) CII1335. Emissions due to electron impact (e + X, Sect. 2.4) on CO₂ (red), H₂O (dark blue), CO (orange), and O₂ (purple) andother processes (hν + X, Sect. 2.5) have been included. The uncertainty in the electron impact emission frequency is derived from the variability in the electron flux during each scan of the FUV spectrograph (see Sect. 2.4.2). hν + CO refers to emissions from the fluorescence of CO (green), while hν + H₂ O refers to the prompt-photodissociation of water (light blue) to produce Lyman-β (see Sect. 2.5).