Rigorousab initiostudy of Allowed and Forbidden transition amplitudes of T12+

We report here 'allowed' and 'forbidden' electromagnetic transition amplitudes among various low lying states of doubly ionized Thallium (T12+) using relativistic coupled cluster method based on Dirac-Fock hybrid basis functions. These transitions are of importance in astrophysics and plasma research. The effect of core correlation, pair correlation and core polarization on these transitions are estimated.