241 research outputs found
QED theory of transition probabilities and line profiles in highly-charged ions
A rigorous QED theory of the spectral line profiles is applied to transition
probabilities in few-electron highly charged ions. Interelectron interaction
corrections are included as well as radiative corrections. Parity nonconserving
(PNC) amplitudes with effective weak interactions between the electrons and
nucleus are also considered. QED and interelectron interaction corrections to
the PNC amplitudes are derived
Calculation of quasi-degenerate energy levels of two-electron ions
Accurate QED calculations of the interelectron interaction corrections for
the , two-electron configurations for ions
with nuclear charge numbers are performed within the line
profile approach. Total energies of these configurations are evaluated.
Employing the fully relativistic treatment based on the {--} coupling
scheme these energy levels become quasi-degenerate in the region . To
treat such states within the framework of QED we utilize the line profile
approach. The calculations are performed within the Coulomb gauge.Comment: 22 pages, 11 figure
QED model of the radiation escape from the matter
A simple model based on QED is presented for the estimation of contribution
of the excited level few-photon decays to the radiation escape from the matter
in the epoch of the cosmological hydrogen recombination. It is shown that apart
from the widely studied two-photon decays, some specific 3-photon decays can
contribute on the level of 0.1% accuracy, required by the recent astrophysical
observations.Comment: 21 pages, 3 figures, 1 Tabl
Asymmetry of the natural line profile for the hydrogen atom
The asymmetry of the natural line profile for transitions in hydrogen-like
atoms is evaluated within a QED framework. For the Lyman-alpha
absorption transition in neutral hydrogen this asymmetry results in an
additional energy shift of 2.929856 Hz. For the transition
it amounts to -1.512674 Hz. As a new feature this correction turns out to be
process dependent. The quoted numbers refer to the Compton-scattering process.Comment: RevTex, 7 Latex pages, 1 figur
Excited states of the helium-antihydrogen system
Potential energy curves for excited leptonic states of the
helium-antihydrogen system are calculated within Ritz' variational approach. An
explicitly correlated ansatz for the leptonic wave function is employed
describing accurately the motion of the leptons (two electrons and positron) in
the field of the helium nucleus and of the antiproton with arbitrary orbital
angular momentum projection onto the internuclear axis. Results for
=0, 1 and 30 are presented. For quasibound states with large values of
and rotational quantum numbers no annihilation and
rearrangement decay channels occur, i. e. they are metastable
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