K. T. Cheng

Electric dipole, quadrupole, and magnetic dipole transition probabilities of ions isoelectronic to the first-row atoms, Li through F☆

Abstract Theoretical wavelengths, oscillator strengths, line strengths, and transition probabilities for the E1, M1, and E2 transitions among states with 2sn2pm configurations are presented for ions isoelectronic to the first-row atoms (Li through F). All ions up to Zn (Z = 30) and representative ions for Z > 30 are included. The multiconfiguration Dirac-Fock technique was used to calculate necessary energy levels and wave functions. All configurations within the n = 2 complex are included to account for electron correlations and intermediate coupling. In addition to relativistic effects arising from the Dirac Hamiltonian and the Breit operator, we included the Lamb shifts of the 1s 1 2 , 2s 1 2 , and 2p 1 2 electrons.

Energy levels, wavelengths, and transition probabilities of Cu-like ions☆

Abstract Wavelengths, oscillator strengths, and transition probabilities for the electric dipole transitions between low-lying states ( n = 4, 5, 6) of Cu-like ions are presented. The data are calculated from relativistic Hartree-Fock wavefunctions.

Excitation energies and oscillator strengths in the silver isoelectronic sequence

Excitation energies and oscillator strengths for electric dipole transitions between low-lying states in the silver isoelectronic sequence are studied using relativistic Hartree-Fock wave functions. For Z ≥ 61, our calculation shows that the ground state of Ag-like ions is 4f2F5/2 rather than 5s 2S1/2. We found a diminishing role of the spin-orbit effect on transitions between levels with high angular momenta. Effects of anticrossings between 4d9 4f2 and 4d10 5l (l = 0,2,4) states at high Z are discussed.

Theoretical photoionization parameters for the noble gases argon, krypton, and xenon

Abstract We report a complete theoretical study of photoionization for the noble gases argon, krypton, and xenon for photon energies up to 6 au (≈160 eV). The cross section σ, angular asymmetry parameter β, spin-polarization parameters ξ, η, and ζ, and total spin-polarization parameter δ are presented in graphs.

Transition probabilities for the resonance transitions of Na-like ions*

Theoretical wavelengths and transition probabilities for the 3S –3P and 3S –4P transitions of Na-like ions are presented. The theoretical data are computed from relativistic Hartree-Fock wave functions. Similar data for additional transitions between low-lying states (n = 3 and 4) of the Fe15+, Mo31+, W63+, and Au68+ ions are also reported. Relativistic effects in the oscillator strengths for the resonance transitions are qualitatively similar to those already observed in the Li sequence. Comparison with available experimental data on wavelengths for Fe15+ and Mo31+ ions shows excellent agreement (1% or better).

Relativistic energy levels of Fe XXI

Energy levels of carbon-like iron Fe XXI, with configurations 2s22p2, 2s2p3 and 2p4 are calculated from the multiconfiguration Dirac-Fock method. The relativistic electron-electron interactions represented by the Breit operator are calculated with wavefunctions of definite angular symmetry instead of averaging over configurations. The authors find that the Breit interaction substantially improves the agreement between theory and experiment on the fine structures of the triplet states, while the Lamb shift corrections are very important in attaining accurate transition energies between configurations. The authors results on energy levels agree with experiment to within 1% for all of the eighteen levels compared, whereas corresponding non-relativistic results are off by 10-30%.

Intershell correlation corrections to the energy levels of the n=2 states of Li-like to F-like ions

The leading intershell correlation corrections to the energy levels of the 2sm2pk (m0-2, k=0-6) configurations of three- to nine-electron ions are calculated on the basis of the Z-expansion theory. These intershell correlations are leading corrections to the multiconfiguration Dirac-Fock (MCDF) results of Cheng and co-workers (1979) and the present study shows that they substantially improve the agreement between the MCDF results and experimental measurements.

RELATIVISTIC AND QUANTUM ELECTRODYNAMIC EFFECTS ON ATOMIC INNER SHELLS

In this chapter our aim is to describe efforts to develop a consistent and accurate theory of atomic inner shells which includes both relativistic and quantum-electrodynamic (QED) effects. We begin with a brief historical description of these efforts in Sec. 1 and continue with more detailed discussions of various theoretical considerations.

Totally polarized electrons from photoionization of outer p12 subshells of rare gases: a relativistic random phase approximation calculation

Abstract Photoelectrons ejected from the outer p 1 2 subshells of the rare gases Ar, Kr, and Xe are shown to be totally polarized at certain energies in the vacuum ultraviolet region of the spectrum. These photoelectrons may provide a favorable source of polarized electrons.