25 research outputs found
Evaluation of the two-photon exchange diagrams for the electron configuration in Li-like ions
We present ab initio calculations of the complete gauge-invariant set of
two-photon exchange graphs for the electron configuration in
Li-like ions. These calculations are an important step towards the precise
theoretical determination of the - transition energy in the
framework of QED.Comment: 17 pages, 6 figure
Two-electron self-energy contribution to the ground state energy of heliumlike ions
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 accurate values for the two-electron part of the ground state
energy of heliumlike ions in the range Z=20-100. The theoretical value of the
ground state energy of heliumlike uranium, based on currently available theory,
is evaluated to be -261382.9(8) eV, without higher order one-electron QED
corrections.Comment: 12 pages, 1 figure, LATE
Improved theoretical prediction for the 2s hyperfine interval in helium ion
We consider the uncertainty of theoretical calculations for a specific
difference of the hyperfine intervals in the 1s and 2s states in a light
hydrogen-like atom. For a number of crucial radiative corrections the result
for hydrogen atom and helium ion appears as an extrapolation of the numerical
data from medium to low Z. An approach to a plausible estimation of the
uncertainty is suggested using the example of the difference
Two-Loop Effects and Current Status of the 4He+ Lamb Shift
We report on recent progress in the treatment of two-loop binding corrections
to the Lamb shift, with a special emphasis on S and P states. We use these and
other results in order to infer an updated theoretical value of the Lamb shift
in 4He+.Comment: 11 pages, nrc1 style; paper presented at PSAS (2006), Venic
QED Effects in Heavy Few-Electron Ions
Accurate calculations of the binding energies, the hyperfine splitting, the
bound-electron g-factor, and the parity nonconservation effects in heavy
few-electron ions are considered. The calculations include the relativistic,
quantum electrodynamic (QED), electron-correlation, and nuclear effects. The
theoretical results are compared with available experimental data. A special
attention is focused on tests of QED in a strong Coulomb field.Comment: 28 pages, 6 tables, 5 figure
Recoil correction to the ground state energy of hydrogenlike atoms
The recoil correction to the ground state energy of hydrogenlike atoms is
calculated to all orders in \alpha Z in the range Z = 1-110. The nuclear size
corrections to the recoil effect are partially taken into account. In the case
of hydrogen, the relativistic recoil correction beyond the Salpeter
contribution and the nonrelativistic nuclear size correction to the recoil
effect, amounts to -7.2(2) kHz. The total recoil correction to the ground state
energy in hydrogenlike uranium (^{238}U^{91+}) constitutes 0.46 eV.Comment: 16 pages, 1 figure (eps), Latex, submitted to Phys.Rev.
Precision Spectroscopy at Heavy Ion Ring Accelerator SIS300
Unique spectroscopic possibilities open up if a laser beam interacts with
relativistic lithium-like ions stored in the heavy ion ring accelerator SIS300
at the future Facility for Antiproton and Ion Research FAIR in Darmstadt,
Germany. At a relativistic factor gamma = 36 the 2P 1/2 level can be excited
from the 2S 1/2 ground state for any element with frequency doubled dye-lasers
in collinear geometry. Precise transition energy measurements can be performed
if the fluorescence photons, boosted in forward direction into the X-ray
region, are energetically analyzed with a single crystal monochromator. The
hyperfine structure can be investigated at the 2P 1/2 - 2S 1/2 transition for
all elements and at the 2P 3/2 - 2S 1/2 transition for elements with Z < 50.
Isotope shifts and nuclear moments can be measured with unprecedented
precision, in principle even for only a few stored radioactive species with
known nuclear spin. A superior relative line width in the order of 5E-7 may be
feasible after laser cooling, and even polarized external beams may be prepared
by optical pumping
Relativistic nuclear recoil corrections to the energy levels of hydrogen-like and high lithium like atoms in all orders in
The relativistic nuclear recoil corrections to the energy levels of
low-laying states of hydrogen-like and high lithium-like atoms in all
orders in are calculated. The calculations are carried out using the
B-spline method for the Dirac equation.
For low the results of the calculation are in good agreement with the
-expansion results. It is found that the nuclear recoil
contribution, additional to the Salpeter's one, to the Lamb shift () of
hydrogen is . The total nuclear recoil correction to the energy
of the transition in lithium-like uranium
constitutes and is largely made up of QED contributions.Comment: 19 pages, latex, accepted for publication in Phys. Rev.
Radiative and interelectronic-interaction corrections to the hyperfine splitting in highly charged B-like ions
The ground-state hyperfine splitting values of high-Z boronlike ions are
calculated. Calculation of the interelectronic-interaction contribution is
based on a combination of the 1/Z perturbation theory and the large-scale
configuration-interaction Dirac-Fock-Sturm method. The screened QED corrections
are evaluated utilizing an effective screening potential approach. Total
hyperfine splitting energies are presented for several B-like ions of
particular interest: {}^{45}Sc{}^{16+}, {}^{57}Fe{}^{21+}, {}^{207}Pb{}^{77+},
and {}^{209}Bi{}^{78+}. For lead and bismuth the experimental values of the 1s
hyperfine splitting are employed to improve significantly the theoretical
results by reducing the uncertainty due to the nuclear effects.Comment: 12 pages, 2 figures, 3 table
Two-time Green function method in quantum electrodynamics of high-Z few-electron atoms
The two-time Green function method in quantum electrodynamics of high-Z
few-electron atoms is described in detail. This method provides a simple
procedure for deriving formulas for the energy shift of a single level and for
the energies and wave functions of degenerate and quasi-degenerate states. It
also allows one to derive formulas for the transition and scattering
amplitudes. Application of the method to resonance scattering processes yields
a systematic theory for the spectral line shape. The practical ability of the
method is demonstrated by deriving formulas for the QED and
interelectronic-interaction corrections to energy levels and transition and
scattering amplitudes in one-, two-, and three-electron atoms. Numerical
calculations of the Lamb shift, the hyperfine splitting, the bound-electron g
factor, and the radiative recombination cross section in heavy ions are also
reviewed.Comment: 92 pages, 39 figures, 7 table