[Ti II] lines observed in η Carinae Sr-filament and lifetimes of the metastable states of Ti+

Forbidden (E2 and M1) transitions among the lowest 37 fine-structure even parity levels of Ti II belonging to 3d24s, 3d3 and 3d4s2 configurations are evaluated in a configuration interaction (CI) calculation in which relativistic effects are accounted for through the full Breit-Pauli interaction in the Hamiltonian matrix. To our knowledge this is the first complete calculation of E2 and M1 transition probabilities among all 37 even parity levels. Comparison of the present gA values with the only other calculated values by Palmeri et al (2008 J. Phys. B: At. Mol. Opt. Phys. 41 125703) for the 29 [Ti II] lines observed in the η Carinae Sr-filament show varying agreement of between 5% → 50%. Agreements among the calculated and observed lifetimes of a few metastable states are mostly good. It is found that single and double core-valence correlation between the n = 3 and 4 complexes are needed for well-converged results.