ELECTRON-IMPACT EXCITATION WITH O-III - OSCILLATOR-STRENGTHS AND COLLISION STRENGTHS

Configuration interaction wavefunctions have been constructed for 26 target states of O III arising from the configuration (1s2) 2s(2)2p2, 2s2p3, 2p4, 2s(2)2p3s, 2s(2)2p3p and 2s(2)2p3d. The calculated threshold energies are in agreement within 5% (except for two states) with the experimental values. A good agreement (better than 10%) between the length and velocity formulations of the oscillator strengths is also found for most of the transitions through differences are quite striking for some of them. The oscillator strengths are tabulated and compared with the earlier results for the 59 optically allowed LS transitions. Calculations have also been done for collision strengths in the LS coupling scheme. These have been computed using the standard R-matrix program for L less-than-or-equal-to 12 and the no-exchange R-matrix program for L > 12. Calculations have, however, been done at energies above the thresholds only. Collision strengths for all the 325 inelastic transitions have been tabulated at six energies in the range 4-12 Ryd and comparisons are made with the most recent distorted-wave calculations. Differences between the two calculations are discussed and the accuracy of the results is assessed.