Fock-space relativistic coupled-cluster calculations of clock transition properties in Pb^2+

We have employed an all-particle Fock-space relativistic coupled-cluster theory to probe 6s^2 ^1S_0 - 6s6p ^3P^o_0 clock transition in an even isotope of Pb^2+. We have computed the excitation energies for several low lying states, E1 and M1 transition amplitudes, and the lifetime of the clock state. Moreover, we have also calculated the electric dipole polarizability of the ground state using perturbed relativistic coupled-cluster theory. To improve the accuracy of results, we incorporated the corrections from the relativistic and QED effects in all our calculations. Contributions from the triple excitations are accounted perturbatively. Our computed excitation energies are in excellent agreement with the experimental values for all states. Our computed lifetime, 10.45×10^6 s, of clock state is ≈ 16% larger than the previously reported value using CI+MBPT [Phys. Rev. Lett. 127, 013201 (2021)]. Based on our analysis, we find that the contributions from the valence-valence electron correlations from higher energy configurations and the corrections from the perturbative triples and QED effects are essential to get accurate clock properties in Pb^2+. Our computed value of dipole polarizability is in good agreement with the available theory and experimental data.