Excitation energies, polarizabilities, multipole transition rates, and lifetimes in ThIV

Excitation energies of the ns(1/2) (n=7-10), np(j) (n=7-9), nd(j) (n=6-8), nf(j) (n=5-7), and ng(j) (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 nl(j)-n(')l(j)('') electric-dipole transitions. Multipole matrix elements (7s(1/2)-6d(j), 7s(1/2)-5f(j), and 5f(5/2)-5f(7/2)) are evaluated to obtain the lifetimes of the 5f(7/2) and 7s(1/2) 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 5f(5/2) 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.