Development of a relativistic coupled-cluster method for one-electron detachment theory: Application to Mn ix, Fe x, Co xi, and Ni xii ions

We have developed a one-electron detachment theory from a closed-shell atomic configuration in the relativistic Fock-space coupled-cluster ansatz. Using this method, we determine sensitivity coefficients to the variation of the fine-structure constant in the first three important low-lying transitions of the astrophysically interesting highly charged Mn ix, Fe x, Co xi, and Ni xii ions. The potential of this method has been assessed by evaluating the detachment energies of the removed electrons and determining the lifetimes of the atomic states in the above ions. To account for the sensitivity of the higher-order relativistic effects, we have used the four-component wave functions of the Dirac-Coulomb-Breit Hamiltonian with the leading-order quantum electrodynamics (QED) corrections. A systematic study has been carried out to highlight the importance of the Breit and QED interactions in the considered properties of the above ions.