68 research outputs found
Environment assisted electron capture
Electron capture by {\it isolated} atoms and ions proceeds by
photorecombination. In this process a species captures a free electron by
emitting a photon which carries away the excess energy. It is shown here that
in the presence of an {\it environment} a competing non-radiative electron
capture process can take place due to long range electron correlation. In this
interatomic (intermolecular) process the excess energy is transferred to
neighboring species. The asymptotic expression for the cross section of this
process is derived. We demonstrate by explicit examples that under realizable
conditions the cross section of this interatomic process can clearly dominate
that of photorecombination
Bound state properties of four-body muonic quasi-atoms
Total energies and various bound state properties are determined for the
ground states in all six four-body muonic
quasi-atoms. These quasi-atoms contain two nuclei of the hydrogen isotopes
, one negatively charged muon and one electron
. In general, each of the four-body muonic
quasi-atoms, where , can be considered as the regular
one-electron (hydrogen) atom with the complex nucleus
which has a finite number of bound states. Furthermore, all properties of such
quasi-nuclei are determined from highly accurate
computations performed for the three-body muonic ions
with the use of pure Coulomb interaction potentials between particles. It is
shown that the bound state spectra of such quasi-atoms are similar to the
spectrum of the regular hydrogen atoms, but there are a few important
differences. Such differences can be used in future experiments to improve the
overall accuracy of current evaluations of various properties of hydrogen-like
systems, including the lowest-order relativistic and QED corrections
Interaction of photons with plasmas and liquid metals: photoabsorption and scattering
Formulas to describe the photoabsorption and the photon scattering by a
plasma or a liquid metal are derived in a unified manner with each other. It is
shown how the nuclear motion, the free-electron motion and the core-electron
behaviour in each ion in the system determine the structure of photoabsorption
and scattering in an electron-ion mixture. The absorption cross section in the
dipole approximation consists of three terms which represent the absorption
caused by the nuclear motion, the absorption owing to the free-electron motion
producing optical conductivity or inverse Bremsstrahlung, and the absorption
ascribed to the core-electron behaviour in each ion with the Doppler
correction. Also, the photon scattering formula provides an analysis method for
experiments observing the ion-ion dynamical structure factor (DSF), the
electron-electron DSF giving plasma oscillations, and the core-electron DSF
yielding the X-ray Raman (Compton) scattering with a clear definition of the
background scattering for each experiment, in a unified manner. A formula for
anomalous X-ray scattering is also derived for a liquid metal. At the same
time, Thomson scattering in plasma physics is discussed from this general point
of view.Comment: LaTeX file: 18 pages without figur
Transition probabilities of 30 Pb II lines of spectrum obtained by emission of a laser-produced plasma
Transition probabilities have been determined for 30 lines of Pb II by measuring the intensities of the emission lines of a laser-produced plasma (LPP) of Pb in an atmosphere of Ar. The plasma has been seen to contain local thermodynamic equilibrium (LTE) and homogeneity; the plasma studied has a temperature of 11 500 K and an electron density of 1016 cm−3. The experimental results obtained during this study have been compared with the experimental and theoretical values given by other authors
Caesium 6P fine-structure mixing and quenching induced by collisions with ground-state caesium atoms and molecules
Irreducible tensor-form of the relativistic corrections to the M1 transition operator
The relativistic corrections to the magnetic dipole moment operator in the
Pauli approximation were derived originally by Drake (Phys. Rev. A 3(1971)908).
In the present paper, we derive their irreducible tensor-operator form to be
used in atomic structure codes adopting the Fano-Racah-Wigner algebra for
calculating its matrix elements.Comment: 26 page
Photoinization cross sections for atomic chlorine using an open-shell random-phase approximation
On the propagation of electromagnetic waves in a medium with a variable refractive index
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