Electron impact ionisation of Ti3+

The electron impact excitation of Ti 3+ from the 3p 6 3d ground state to terms of the 3p 5 3d 2 configuration is calculated using a ten-state R-matrix expansion. Three of these terms lie above the ionisation threshold and this calculation shows that the contribution of excitation-autoionisation from these terms dominates the ionisation cross section over a wide range of energies. The discrepancy between the earlier distorted-wave calculations of Griffin et al. (1982) and the experimental ionisation measurements of Falk et al. (1981) has been largely removed.