Excitation energies, polarizabilities, multipole transition rates, and lifetimes in Th IV

Excitation energies of the ns1∕2 (n=7–10), npj (n=7–9), ndj (n=6–8), nfj (n=5–7), and ngj (n=5,6) states in Th IV are evaluated. First-, second-, third-, and all-order Coulomb energies and first- and second-order Coulomb-Breit energies are calculated. Reduced matrix elements, oscillator strengths, transition rates, and lifetimes are determined for the 96 possible nlj-n′lj′′ electric-dipole transitions. Multipole matrix elements (7s1∕2-6dj, 7s1∕2-5fj, and 5f5∕2-5f7∕2) are evaluated to obtain the lifetimes of the 5f7∕2 and 7s1∕2 states. Matrix elements are calculated using both relativistic many-body perturbation theory, complete through third order, and a relativistic all-order method restricted to single and double excitations. Scalar and tensor polarizabilities for the 5f5∕2 ground state in Th3+ are calculated using relativistic third-order and all-order methods. These calculations provide a theoretical benchmark for comparison with experiment and theory.