Theoretical Research On The Transition Energy And Oscillator Strength Of Lithium-Like Systems

The main idea of the full core plus correlation (FCPC) method and its important achievements are reviewed. This method are extended to calculate the transition energy of 1s2ns (n = 2, 3, and 4) --1s23p for the lithium-like systems with nuclear charge from Z=11 to 20 . The non-relativistic energies are calculated by using Rayleigh-Ritz(s variation method(when calculate the energies,the FCPC wavefunction are obtained). The relativistic and mass-polarization effects on the energies are included as the first-order perturbation(The relativistic effect include the correction to kinetic energy, the Darwin term, the electron-electron contact term, the orbit-orbit interaction). The quantum -electrodynamics (QED) contributions to the transition energy are also evaluated by using effective nuclear charge. The oscillator strength of 1s22s-1s23p, 1s24s-1s23p are calculated by the FCPC wavefunction and the corresponding transitional energy.The fine structure is calculated by using the spin-orbit and the spin-other-orbit interaction operators. The results are in excellent agreement with experimental data available in the literature.Our theoretical result proved that the FCPC method is good to calculated the transitional energy of lithium-like systems. And the wavefunction is precise in all the configuration space.