A. N. Artemyev

QED treatment of electron correlation in Li-like ions

A systematic QED treatment of the electron correlation is presented for ions along the lithium isoelectronic sequence. We start with the zeroth-order approximation that accounts for a part of the electron-electron interaction by a local model potential introduced into the Dirac equation. The residual electron correlation is treated by perturbation theory. A rigorous QED evaluation is presented for the first two terms of the perturbative expansion; the third-order contribution is calculated within the many-body perturbation theory. We report accurate numerical results for the electronic-structure part of the ionization potential for the n=2 states of all Li-like ions up to uranium.

A DFT variational approach to Hooke's atom based on local-scaling transformations

The local-scaling transformation version of density functional theory, LS-DFT, is employed in order to construct energy functionals for Hookes atom. The components of the energy are analyzed and the resulting exchange and correlation potentials are compared with the exact ones. In addition, the representation of the exact one-particle density in terms of the various components of the total energy density is discussed.

Direct evaluation of the two-electron self-energy corrections to the ground state energy of lithium-like ions

We present a calculation of the two-electron self-energy corrections to the ground state energy of Li-like ions in the range Z = 20-100. The calculation is performed both for point and extended nuclei to all orders in .

A finite B-spline basis set for accurate diatomic molecule calculations

A finite basis set particularly adapted for solving the Hartree–Fock equation for diatomic molecules in prolate spheroidal coordinates has been constructed. These basis functions have been devised as products of B‐splines times associated Legendre polynomials. Due to the large number of B‐splines, the resulting set of eigenfunctions is amply distributed over excited states. This gives the possibility of using these basis sets to calculate sums over excited states, appearing in various orders of perturbation theory. As an illustration, the second‐order corrections to the ground‐state energy of some atoms and diatomic molecules with closed electron shells have been calculated.

Correlation and quantum electrodynamic effects on the radiative lifetime and relativistic nuclear recoil in Ar13+ and Ar14+ ions

The radiative lifetime and mass isotope shift of the 1s22s22p 2P3/2 - 2P1/2 M1 transition in Ar13+ ions have been determined with high accuracies using the Heidelberg electron beam ion trap. This fundamentally relativistic transition provides unique possibilities for performing precise studies of correlation and quantum electrodynamic effects in many-electron systems. The lifetime corresponding to the transition has been measured with an accuracy of the order of one per thousand. Theoretical calculations predict a lifetime that is in significant disagreement with this high-precision experimental value. Our mass shift calculations, based on a fully relativistic formulation of the nuclear recoil operator, are in excellent agreement with the experimental results and confirm the absolute necessity to include relativistic recoil corrections when evaluating mass shift contributions even in medium-Z ions.

Lamb shift calculations for high-Z lithium like ions

AbstractWe present ab initio calculations of the complete gauge invariant set of the self energy and vacuum polarization screening diagrams for the 2pn

Electronic-structure kinetic-energy functional based on atomic local-scaling transformations

2{text{p}}_{{text{1/2}}} - 2{text{s}}

Benchmarking high-field few-electron correlation and QED contributions in Hg75+ to Hg78+ ions: II. Theory

n transition in Li like ions. Various contributions to the transition energy are collected. The accuracy of theoretical predictions is discussed.