416 research outputs found

    Multiplet effects on the L(2,3) fluorescence yield of multiply ionized Ar

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    The 2p fluorescence yield of argon in the presence of 0 to 6 3p holes was calculated by statistically averaging the fluorescence yields of initial state that consist of individual multiplet configurations. These configurations were formed by coupling the 2p vacancy to the partially filled 3p shell. Results agree reasonably well with experimental fluorescence yields deduced from ion-atom collision measurements

    Feasibility of coherent X-ray production by X-ray pumping

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    It is suggested that coherent X-rays can be produced by inverting the electron population in a suitable target, such as Li, through irradiation with X-rays generated by fast electrons traversing an electromagnetic field (as in a storage ring). Conditions to be satisfied by target and radiation parameters are stated, and examples given

    Atomic electron correlation in nuclear electron capture

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    The effect of electron-electron Coulomb correlation on orbital electron capture by the nucleus was treated by the multiconfigurational Hartree-Fock approach. The theoretical Be-7 L/K capture ratio was found to be 0.086, and the Ar-37 M/L ratio, 0.102. Both ratios were smaller than the independent particle predictions. Measurements exist for the Ar M/L ratio, and agreement between theory and experiment was excellent

    Interpretation of the silver L X-ray spectrum

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    Silver L X-ray energies were calculated using theoretical binding energies from relaxed orbital relativistic Hartree-Fock-Slater calculations. Theoretical X-ray energies are compared with experimental results

    Exchange and relaxation effects in low-energy radiationless transitions

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    The effect on low-energy atomic inner-shell Coster-Kronig and super Coster-Kronig transitions that is produced by relaxation and by exchange between the continuum electron and bound electrons was examined and illustrated by specific calculations for transitions that deexcite the 3p vacancy state of Zn. Taking exchange and relaxation into account is found to reduce, but not to eliminate, the discrepancies between theoretical rates and measurements

    Atomic electron energies including relativistic effects and quantum electrodynamic corrections

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    Atomic electron energies have been calculated relativistically. Hartree-Fock-Slater wave functions served as zeroth-order eigenfunctions to compute the expectation of the total Hamiltonian. A first order correction to the local approximation was thus included. Quantum-electrodynamic corrections were made. For all orbitals in all atoms with 2 less than or equal to Z less than or equal to 106, the following quantities are listed: total energies, electron kinetic energies, electron-nucleus potential energies, electron-electron potential energies consisting of electrostatic and Breit interaction (magnetic and retardation) terms, and vacuum polarization energies. These results will serve for detailed comparison of calculations based on other approaches. The magnitude of quantum electrodynamic corrections is exhibited quantitatively for each state

    Theoretical L-shell Coster-Kronig energies 11 or equal to z or equal to 103

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    Relativistic relaxed-orbital calculations of L-shell Coster-Kronig transition energies have been performed for all possible transitions in atoms with atomic numbers. Hartree-Fock-Slater wave functions served as zeroth-order eigenfunctions to compute the expectation of the total Hamiltonian. A first-order approximation to the local approximation was thus included. Quantum-electrodynamic corrections were made. Each transition energy was computed as the difference between results of separate self-consistent-field calculations for the initial, singly ionized state and the final two-hole state. The following quantities are listed: total transition energy, 'electric' (Dirac-Hartree-Fock-Slater) contribution, magnetic and retardation contributions, and contributions due to vacuum polarization and self energy

    Eine DSL für Harel-Statecharts mit PetitParser

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    Eine AuDSL genannte domänenspezifische Sprache zur Beschreibung von Harel-Statechart-Automaten wird benutzt, um exemplarisch die Eignung von PetitParser, einem zum Helvetia-Framework gehörenden Parser-Combinator, als Baustein einer Language-Workbench zu erproben. Verwendet wird die Pharo1-Implementierung von Petit-Parser. Neben der Implementierung der AuDSL als PetitParser-Skript wird auch die Laufzeitumgebung vorgestellt, die die Ausführung der Automaten ermöglicht. Die Einbettung von AuDSL-Texten in die Wirtssprache Smalltalk wird gezeigt. Die gemachten Erfahrungen zeigen grundsätzlich die Einfachheit des Baus von DSLs mit PetitParser. Die Integration einer DSL in die Werkzeuge der Entwicklungsumgebung bleibt ohne die Nutzung des Helvetia-Frameworks aber unvollständig. Die Übertragbarkeit der Vorgehensweise auf andere Programmiersprachen (z. B. Scala) wird angedeutet. --

    Orbital electron capture by the nucleus

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    The theory of nuclear electron capture is reviewed in the light of current understanding of weak interactions. Experimental methods and results regarding capture probabilities, capture ratios, and EC/Beta(+) ratios are summarized. Radiative electron capture is discussed, including both theory and experiment. Atomic wave function overlap and electron exchange effects are covered, as are atomic transitions that accompany nuclear electron capture. Tables are provided to assist the reader in determining quantities of interest for specific cases

    Relativistic electrostatic slater integrals, 2 or equal to Z or equal to 106

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    Two-electron electrostatic interaction integrals were computed with Dirac-Hartree-Fock-Slater wave functions. Results are listed for all orbitals in atoms with atomic numbers from Z = 2 through Z = 106
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