Accurate cross sections for excitation of resonance transitions in atomic oxygen

Electron collision excitation cross sections for the resonance 2 p 4 3 P –2 p 3 3 s 3 S o , 2 p 4 3 P –2 p 3 3 d 3 D o , 2 p 4 3 P –2 p 3 3 s 3 D o , 2 p 4 3 P –2 p 3 3 s 3 P o , and 2 p 4 3 P –2 s 2 p 5 3 P o transitions have been calculated by using the R matrix with a pseudostates approach for incident electron energies from near threshold to 100 eV. The excitation of these transitions gives rise to strong atomic oxygen emission features at 1304, 1027, 989, 878, and 792 Å in the spectra of several planetary atmospheres. We included 22 spectroscopic bound and autoionizing states and 30 pseudostates in the close‐coupling expansion. The target wave functions are chosen to properly account for the important correlation and relaxation effects. The effect of coupling to the continuum is included through the use of pseudostates. The contribution of the ionization continuum is significant for resonance transitions. Measured absolute direct excitation cross sections of O I are reported by experimental groups from the Jet Propulsion Laboratory and Johns Hopkins University. Good agreement is noted for the 2 p 4 3 P –2 p 3 3 s 3 S o transition (λ1304 Å) with measured cross sections from both groups that agree well with each other. There is disagreement between experiments for other transitions. Our results support the measured cross sections from the Johns Hopkins University for the 2 p 4 3 P –2 p 3 3 d 3 D o and 2 p 4 3 P –2 p 3 3 s 3 D o transitions, while for the 2 p 4 3 P –2 p 3 3 s 3 P o transition the agreement is switched to the measured cross sections from the Jet Propulsion Laboratory.