Investigating properties of Cl− and Au− ions using relativistic many-body methods

Abstract

We investigate the ground state properties of singly charged chlorine (Cl−) and gold (Au−) negative ions by employing four-component relativistic many-body methods. In our approach, we attach an electron to the respective outer orbitals of chlorine (Cl) and gold (Au) atoms to determine the Dirac–Fock (DF) wave functions of the ground state configurations of Cl− and Au−, respectively. As a result, all the single-particle orbitals see the correlation effects due to the appended electron of the negative ion. After obtaining the DF wave functions, lower-order many-body perturbation methods, random-phase approximation, and coupled-cluster (CC) theory in the single and double approximation are applied to obtain the ground state wave functions of both Cl− and Au− ions. Then, we adopt two different approaches to the CC theory—a perturbative approach due to the dipole operator to determine electric dipole polarizability and an electron detachment approach in the Fock-space framework to estimate ionization potential. Our calculations are compared with the available experimental and other theoretical results.