Oscillator strengths for dipole transitions in neutral oxygen

Abstract

Accurate bound-state wavefunctions obtained by the close-coupling method in the frozen-cores approximation are used to calculate oscillator strengths for neutral oxygen. Results include transition probabilities for all terms of O I (excited and ground states) obtained by adding an s, p or d electron to the ground-configuration terms of O II. The authors consider Rydberg series up to n=6. Many of the transitions are parentage forbidden and configuration mixing provides the driving mechanism. Results agree with experiment to within 10%. Strong intercombination lines are observed in oxygen; the effects of deviations from LS coupling on the allowed transitions presented are discussed by using the unpublished results from an independent investigation by Zeippen (1977). Calculations include the continuum region, and the photoionisation cross section for oxygen is obtained. These results are in very satisfactory agreement with close-coupling calculations by Taylor and Burke 1976.