Configuration-interaction effects on the electron-impact ionization of Ti3+

Using a recently developed, unified version of both R-matrix and distorted-wave methods, we have carried out new calculations for the electron-impact ionization of Ti3+ and found that the previous calculations of Griffin et al. (Phys. Rev. A, vol. 25, p.1374-82, 1982) are incorrect. Contrary to one of the major conclusions of that paper, coupling between the three autoionizing and the sixteen bound LS terms of the 3p53d2 configuration is not important. However, the other major conclusion of that paper that the inclusion of singly-excited states is necessary to provide an alternate decay path for resonances remains valid. Further calculations including configuration-interaction (CI) mixing with correlation configurations formed by the double-electron promotions 3p2 to 3d2 were necessary to achieve reasonable agreement with experiment. A larger close-coupling calculation which included 3p64s and 3p53d4s target states and the corresponding 3p2 to 3d2 correlation configurations provided further improvements in the results. Potential problems with pseudo-resonances are found to be effectively diagnosed by comparison of distorted-wave and R-matrix results.