Wang Zhi-Wen

ENERGY AND OSCILLATOR STRENGTH FOR LITHIUM ATOM

The excitation energies of the excited states 1s2nl (l = s,p,d, and f, and 6 ≤ n ≤ 9) and the dipole oscillator strengths of the 1s22s - 1s2np, 1s22p - 1s2nd and 1s23d - 1s2nf transitions for lithium atom are calculated by using the full core plus correlation method.

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

We extend the Hamiltonian method of the full-core plus correlation (FCPC) by minimizing the expectation value to calculate the non-relativistic energies and the wave functions of 1s22s states for the lithium-like systems from Z = 41 to 50. The mass-polarization and the relativistic corrections including 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 explored by using the effective nuclear charge formula. The ionization potential and term energies of the ground states 1s22s are derived and compared with other theoretical calculation results. It is shown that the FCPC methods are also effective for theoretical calculation of the ionic structure for high nuclear ion of lithium-like systems.

Charge density at the nucleus and radial behavior of ground state for lithium-like ions with Z = 21 to 30

By using the full-core plus correlation (FCPC) type wave functions, the accurate charge densities (0) at the nucleus and the radial expectation values of the ground states for the lithium-like systems with Z = 21 to 30 are obtained. The determinantal conditions and the electron-nucleus cusp condition are used to calculate the inequalities of the upper and the lower bounds to (0) with two or more expectation values. These inequalities, derived by Angulo and Dehesa [Phys. Rev. A 44 1516 (1991)], are verified to be also valid for these ions with higher nuclear charge. The present results show that the wave functions used in this paper are satisfactory in the whole configuration space for these ions with higher nuclear charge.

Energy and fine structure of 1s 2 np(n≤9) states for lithium-like systems from Z=11 to 20

A new variation method is extended to study the atomic systems with higher nuclear charges and in more highly excited states. The non-relativistic energies of 1s2np (n≤ 9) states for the lithium-like systems from Z=11 to 20 are calculated using a full-core-plus-correlation method with multi-configuration interaction wavefunctions. Relativistic and mass-polarization effects on the energy are calculated as the first-order perturbation corrections. The fine structures are determined from the expectation values of spin-orbit and spin-other-orbit interaction operators in the Pauli–Breit approximation. The quantum-electrodynamics correction is also included. Our results are compared with experimental data in the literature.

Inequalities of the electron density at the nucleus and radial expectation values of the ground state for the lithium isoelectronic sequence

The electron density at the nucleus, ρ(0) and the radial expectation values, (-2≤n≤10), of the ground state for the lithium isoelectronic sequence are calculated with a full core plus correlation (FCPC) wavefunctions. By using these obtained expectation values, the accurate inequalities of the electron density at the nucleus and the radial expectation values derived by Galvez and Porras for these systems are examined and verified. The final results show that FCPC wavefunctions used in this work can give satisfactory results in full configuration space.

The excitation energies and term energies of the excited states 1s2ns (n=3,4,5) and 1s2nf (n=4,5) of lithium-like systems of Z=11-20

In this paper, the full-core plus correlation (FCPC) and the Ritz method is extended to calculate the non-relativistic energies of 1s2ns (n=3,4,5) and 1s2nf (n=4,5) states and the wavefunctions of the lithium-like systems from Z=11-20. The mass-polarization and the relativistic correction including the kinetic-energy correction, the Darwin term, the electron-electron contact term and the orbit-orbit interaction are evaluated perturbatively as the first-order correction. The contribution from quantum electrodynamic is also included by using the effective nuclear charge formula. The excited energies, the term-energy and fine structure, are given and compared with the other theoretical calculation and experimental results. It is shown that the correlative wave in the FCPC method embodies well the strong correlation between the 1s2 core and the valence electron.

Calculations of 2s2S1/2-2p2P1/2,3/2 Transition Energies for Lithium-Like Systems from Na IX to Ca XVIII

The transition energies (2s2S1/2 - 2p2P1/2,3/2) of lithium-like systems with nuclear charge from Z = 11-20 are calculated by using a full-core plus correlation method. Relativistic and mass-polarization effects on the energies are included as the first-order perturbation corrections. The quantum-electrodynamics contributions to the transition energy are evaluated by using effective nuclear charge. Our results are in excellent agreement with previous theoretical and experimental data available in the literature.

Variational Calculation of the Intrashell 2p2 3Pe States for Heliumlike N5+ and O6+ Ions

Doubly excited intrashell 2p2 3Pe states in heliumlike N5+ and O6+ ions are calculated by using the original Slater-type wave function and the modified configuration interaction wave function. Using the modified Slater-type wave function having up to 393 and 276 terms for N5+ and O6+, we predicted the energy positions of the discrete 2p2 3Pe states for these two heliumlike ions. They are -11.140748676 a.u. and -14.726670741 a.u., respectively. Several expectation values of rin and r12m (-1 ≤ n ≤ 1, and -1 ≤ m ≤ 2) are also given in the present letter. The present results indicate that the modified Slater-type wave function in which r coordinates are incorporated is effective and powerful for the description of the 2p2 3Pe state showing strong correlation effect in two-electron systems.

Energy of 1s2snp 4P States for the Lithium Isoelectronic Sequence

The nonrelativistic energies of the core-excited 1s2snp 4P (n = 2, 3, 4, 5) states for the lithium isoelectronic sequence from Be II to O VI are calculated with a full core plus correlation method using multiconfiguration interaction wavefunctions. The relativistic and mass-polarization effects on the energy are evaluated as the first order perturbation theory. Our predicted energies are lower than other theoretical results. They show that this full core plus correlation method is useful for the core-excited systems.

On the 1s24d Fine Structures of B III and Ne VIII

The fine structure of lithium-like 1s24d states in the literature behaves irregularly as a function of Z. The fine structures of the B III and Ne VIII fall well below the isoelectronic curve. The term energies of these two systems in the data tables also give worse agreement with the theoretical prediction. In this work, we show that the reason for this unusual situation is caused by a misidentification in the original spectra. When the correct identifications are made, the fine structures of both systems fall on the isoelectronic curve and the agreement between theory and experiment is excellent.