Excitation energies, oscillator strengths, and lifetimes of levels along the gold isoelectronic sequence

Energies of ns1∕2(n=6-9) , npj(n=6-8) , ndj(n=6-7) , and 5fj states in neutral Au and Au-like ions with nuclear charges Z=80–83 are calculated using relativistic many-body perturbation theory. Reduced matrix elements, oscillator strengths, transition rates and lifetimes are determined for the 30 possible nlj−n′lj′′ electric-dipole transitions. Results for a limited number states ns1∕2 , npj(n=6–7) and 6dj are obtained in the relativistic single-double (SD) approximation, where single and double excitations of Dirac-Fock wave functions are included to all orders in perturbation theory. Using SD wave functions, accurate values are obtained for energies of the eight lowest states and for the fourteen possible electric-dipole matrix elements between these states. With the aid of the SD wave functions, we also determine transition rates and oscillator strengths for the fourteen transitions together with lifetimes of 6pj , 7pj , and 6dj levels. We investigate the hyperfine structure in Hg  II and Tl  III . The hyperfine A values are determined for 6s1∕2 and 6pj states in 199Hg+ , 201Hg+ , and 205Tl2+ isotopes. These calculations provide a theoretical benchmark for comparison with experiment and theory.