cross sections for production of the CO⁺(B²Σ⁺→X²Σ⁺) fluorescence by photoionization of CO

Cross sections for production of the CO+(B²Σ+ → X²Σ+) first negative bands by photoionization of CO were measured by synchrotron radiation of wavelengths from λλ175 to 635 Å. The cross sections reach a peak value of 1.57 × 10−18 cm² at λ560 Å and decrease monotonically to a value of 2.5 × 10−19 cm² at λ180 Å The excitation rate at 1 AU for mean solar activity is d=1.9 × 10−8 s−1 molecule−1.