742 research outputs found
Relativistic transition wavelenghts and probabilities for spectral lines of Ne II
Transition wavelengths and probabilities for several 2p4 3p - 2p4 3s and 2p4
3d - 2p4 3p lines in fuorine-like neon ion (NeII) have been calculated within
the multiconfiguration Dirac-Fock (MCDF) method with quantum electrodynamics
(QED) corrections. The results are compared with all existing experimental and
theoretical data
Coordinate-space approach to the bound-electron self-energy: Self-Energy screening calculation
The self-energy screening correction is evaluated in a model in which the
effect of the screening electron is represented as a first-order perturbation
of the self energy by an effective potential. The effective potential is the
Coulomb potential of the spherically averaged charge density of the screening
electron. We evaluate the energy shift due to a , ,
, or electron screening a , ,
, or electron, for nuclear charge Z in the range . A detailed comparison with other calculations is made.Comment: 54 pages, 10 figures, 4 table
Hyperfine Quenching of the Level in Zn-like Ions
In this paper, we used the multiconfiguration Dirac-Fock method to compute
with high precision the influence of the hyperfine interaction on the
level lifetime in Zn-like ions for stable and some
quasi-stable isotopes of nonzero nuclear spin between Z=30 and Z=92. The
influence of this interaction on the separation energy is also calculated for the same ions
The nonrelativistic limit of Dirac-Fock codes: the role of Brillouin configurations
We solve a long standing problem with relativistic calculations done with the
widely used Multi-Configuration Dirac-Fock Method (MCDF). We show, using
Relativistic Many-Body Perturbation Theory (RMBPT), how even for relatively
high-, relaxation or correlation causes the non-relativistic limit of states
of different total angular momentum but identical orbital angular momentum to
have different energies. We show that only large scale calculations that
include all single excitations, even those obeying the Brillouin's theorem have
the correct limit. We reproduce very accurately recent high-precision
measurements in F-like Ar, and turn then into precise test of QED. We obtain
the correct non-relativistic limit not only for fine structure but also for
level energies and show that RMBPT calculations are not immune to this problem.Comment: AUgust 9th, 2004 Second version Nov. 18th, 200
Two-loop self-energy contribution to the Lamb shift in H-like ions
The two-loop self-energy correction is evaluated to all orders in Z\alpha for
the ground-state Lamb shift of H-like ions with Z >= 10, where Z is the nuclear
charge number and \alpha is the fine structure constant. The results obtained
are compared with the analytical values for the Z\alpha-expansion coefficients.
An extrapolation of the all-order numerical results to Z=1 is presented and
implications of our calculation for the hydrogen Lamb shift are discussed
QED and relativistic corrections in superheavy elements
In this paper we review the different relativistic and QED contributions to
energies, ionic radii, transition probabilities and Land\'e -factors in
super-heavy elements, with the help of the MultiConfiguration Dirac-Fock method
(MCDF). The effects of taking into account the Breit interaction to all orders
by including it in the self-consistent field process are demonstrated. State of
the art radiative corrections are included in the calculation and discussed. We
also study the non-relativistic limit of MCDF calculation and find that the
non-relativistic offset can be unexpectedly large.Comment: V3, May 31st, 200
QED self-energy contribution to highly-excited atomic states
We present numerical values for the self-energy shifts predicted by QED
(Quantum Electrodynamics) for hydrogenlike ions (nuclear charge ) with an electron in an , 4 or 5 level with high angular momentum
(). Applications include predictions of precision transition
energies and studies of the outer-shell structure of atoms and ions.Comment: 20 pages, 5 figure
Relativistic Calculation of two-Electron one-Photon and Hypersatellite Transition Energies for Elements
Energies of two-electron one-photon transitions from initial double K-hole
states were computed using the Dirac-Fock model. The transition energies of
competing processes, the K hypersatellites, were also computed. The
results are compared to experiment and to other theoretical calculations.Comment: accepted versio
Analysis of X-ray spectra emitted from laser-produced plasmas of uranium
In this paper, we used the multiconfiguration Dirac-Fock method to generate
theoretical X-ray spectra for Co-, Ni-, Cu-, Zn-, Ga-, Ge-, As-, Se-, Br-, Kr-,
and Rb-like uranium ions. Using the distribution of these ions in a
laser-produced plasma, for different plasma temperatures, we generate
theoretical spectra, which are compared to experimental data
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