Theoretical calculation of ionization potential and term energy of the ground states 1s22s of lithium-like systems from Z=21 to 30

Abstract

In the paper, the full-core plus correlation (FCPC) and the minimizing the expectation value of the Hamiltonian method is extended to calculate the non-relativistic energies and the wave functions of 1s22s states for the lithium-like systems from Z=21 to 30. The mass-polarization and the relativistic correction included the kinetic-energy correction, the Darwin term, the electron-electron contact term, and the orbit-orbit interaction are calculated perturbatively as first-order correction. The contribution from quantum electrodynamic (QED) is also included by using the effective nuclear charge formula. The ionization potential and term energies of the ground states 1s22s are given and compared with other's theoretical calculation and experimental results. It is shown that the FCPC methods are also effective to theoretical calculation of the ionic structure for high nuclear ion of lithium-like systems.

Ionization energies and term energies of the ground states 1s22s of lithium-like systems

“…We have extended the FCPC method to calculate ionization energies and term energies for lithium-like atomic systems for Z = 41-50, with higher nuclear charge than that in previous literature. [23] Our calculated term energies agree well with the theoretical results obtained by 1/Z expansion method in Ref. [3].…”

“…Recently, this method has also been applied to the excited states 1s 2 nl (l = s, d, and f, n ≤ 5) of lithium-like systems for Z = 11-20 [16] and the ground states of the systems with Z = 21-30. [17] Later on, this method was used to calculate the energy and fine structure of 1s 2 np states, [18] and the dipole oscillator strengths for 1s 2 2p-1s 2 nd and 1s 2 3d-1s 2 nf (n ≤ 9) transitions of lithiumlike systems with Z = 11-20. [19,20] A natural extension is to test this method on the system with higher nuclear charge and in the higher energy region.…”