Quantum defect theory VIII. Resonances in the collision strengths for O+ 2p3 2D3/2-2D5/2

Transitions between the levels 2 D 3/2 , 2 D 5/2 of O + 2p 3 , produced by electron impact, are of importance in determining the relative intensities of the lines 2 D J - 4 S observed in gaseous nebulae. Saraph, Seaton and Shemming have made calculations for energies above the threshold for excitation of 2p 3 2 P. Below this threshold the 2 D 3/2 - 2 D 5/2 cross section contains series of resonances converging on 2 P. The reactance matrices of Saraph et al. are extrapolated to energies below the 2 P threshold, and the cross sections are calculated using resonance theory for the case of degenerate closed channels, as developed by Gailitis in 1963 and discussed in the paper `Quantum defect theory VII'.