Related papers: Ionization energies along beryllium isoelectronic …
The two-electron self-energy contribution to the ground state energy of heliumlike ions is calculated both for a point nucleus and an extended nucleus in a wide interval of Z. All the two-electron contributions are compiled to obtain most…
The polarizabilities and hyperpolarizabilities of the Be$^+$ ion in the $2^2S$ state and the $2^2P$ state are determined. Calculations are performed using two independent methods: i) variationally determined wave functions using Hylleraas…
With the consideration of identity principle and atomic shell structure, we calculated the ground state energy of Lithium atom and Beryllium atom based on variational method, which accords quite well with the experimental results.
Relativistic calculations of the second- and third-order contributions in magnetic field to the Zeeman splitting in boronlike ions are presented for the wide range of nuclear charge numbers $Z=6$--$92$. The interelectronic-interaction…
High precision variational calculations in Hylleraas coordinates are presented for all singlet and triplet $P$-states of helium up to principal quantum number $n = 35$ with a uniform accuracy of 1 part in $10^{22}$ for the nonrelativistic…
Since the '30s the interatomic potential of the beryllium dimer Be$_2$ has been both an experimental and a theoretical challenge. Calculating the ground-state correlation energy of Be$_2$ along its dissociation path is a difficult problem…
The nuclear recoil effect on the g factor of highly charged Li-like ions is evaluated in the range Z=10-92. The calculations are performed using the 1/Z perturbation theory. The one-electron recoil contribution is evaluated within the fully…
For superheavy elements with atomic numbers $120\leq Z \leq 170$, the concept of the ground-state configuration is being reexamined. To this end, relativistic calculations of the electronic structure of the low-lying levels are carried out…
The successive ionization potentials (IPs) and electron affinities (EAs) for superheavy elements with $111 \leq Z \leq 114$, namely, Rg, Cn, Nh, and Fl are reexamined using the relativistic Fock-space coupled-cluster method with…
We use recently developed method of accurate atomic calculations which combines linearized single-double coupled cluster method with the configuration interaction technique to calculate ionisation potentials, excitation energies, static…
Bound state properties of the four-electron lithium ion Li$^{-}$ in its ground $2^{2}S-$state and isotope-subsistuted ${}^{6}$Li$^{-}$ and ${}^{7}$Li$^{-}$ ions in their ground $2^1S-$state(s) are determined from the results of accurate,…
Helium (He) is the ideal atom to perform tests of ab-initio calculations in two-electron systems that consider all known effects, including quantum-electrodynamics and nuclear-size contributions. Recent state-of-the-art calculations and…
QED corrections to the $g$ factor of Li-like and B-like ions in a wide range of nuclear charges are presented. Many-electron contributions as well as radiative effects on the one-loop level are calculated. Contributions resulting from the…
Relativistic calculations for the $g$ factor of the lowest excited states $2p_{1/2}$ and $2p_{3/2}$ of lithium-like ions over a wide range of the nuclear charge numbers $Z=10-92$ are presented. Interelectronic interaction is considered…
In this paper we present results of ab-initio calculations for the beryllium dimer with basis set of Slater-type orbitals (STOs). Nonrelativistic interaction energy of the system is determined using the frozen-core full configuration…
Recent measurements of the ionization energies of the Rydberg $^1P$ states of helium for principal quantum number $n = 24$ and higher present a new challenge to theoretical atomic physics. A long-standing obstacle to high precision atomic…
The nuclear-polarization corrections to the energy levels of highly charged ions are systematically investigated to leading order in the fine-structure constant. To this end, the notion of effective photon propagators with…
We consider electron impact single ionization of an atom at large energy-momentum transfer in the nearly Bethe-ridge kinematics. For evaluation of the ionization amplitude, a plane wave Born series is employed. A regularization procedure is…
We study static-field ionization of He-like ions with nuclear charge number in the range of $2\le Z \le 36$. Both the tunneling and over-the-barrier regimes are considered. We calculate the ionization rates by three approximate methods: a…
A G{\"o}rling-Levy (GL)-based perturbation theory along the range-separated adiabatic connection is assessed for the calculation of electronic excitation energies. In comparison with the Rayleigh-Schr{\"o}dinger (RS)-based perturbation…