The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Victor V. Flambaum - One of the best experts on this subject based on the ideXlab platform.
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Calculation of Atomic Spectra and transition amplitudes for the superheavy element Db (Z =105)
Physical Review A, 2018Co-Authors: B. G. C. Lackenby, V. A. Dzuba, Victor V. FlambaumAbstract:Atomic Spectra and other properties of superheavy element dubnium (Db, Z=105) are calculated using recently developed method combining configuration interaction with perturbation theory (the CIPT method, Dzuba et al, Phys. Rev. A, {\bf 95}, 012503 (2017)). These include energy levels for low-lying states of Db and Db~II, electric dipole transition amplitudes from the ground state of Db, isotope shift for these transitions and ionisation potential of Db. Similar calculations for Ta, which is lighter analog of Db, are performed to control the accuracy of the calculations.
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calculation of Atomic Spectra and transition amplitudes for the superheavy element db z 105
Physical Review A, 2018Co-Authors: B. G. C. Lackenby, V. A. Dzuba, Victor V. FlambaumAbstract:Atomic Spectra and other properties of superheavy element dubnium (Db, Z=105) are calculated using recently developed method combining configuration interaction with perturbation theory (the CIPT method, Dzuba et al, Phys. Rev. A, {\bf 95}, 012503 (2017)). These include energy levels for low-lying states of Db and Db~II, electric dipole transition amplitudes from the ground state of Db, isotope shift for these transitions and ionisation potential of Db. Similar calculations for Ta, which is lighter analog of Db, are performed to control the accuracy of the calculations.
Benoît Grémaud - One of the best experts on this subject based on the ideXlab platform.
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Semiclassical analysis of real Atomic Spectra beyond Gutzwiller's approximation.
Physical review. E Statistical nonlinear and soft matter physics, 2005Co-Authors: Benoît GrémaudAbstract:Real Atomic systems, like the hydrogen atom in a magnetic field or the helium atom, whose classical dynamics are chaotic, generally present both discrete and continuous symmetries. In this paper, we explain how these properties must be taken into account in order to obtain the proper (i.e., symmetry projected) h expansion of semiclassical expressions like the Gutzwiller trace formula. In the case of the hydrogen atom in a magnetic field, we shed light on the excellent agreement between present theory and exact quantum results.
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Semiclassical analysis of real Atomic Spectra beyond Gutzwiller's approximation.
Physical Review E, 2005Co-Authors: Benoît GrémaudAbstract:Real Atomic systems, like the hydrogen atom in a magnetic field or the helium atom, whose classical dynamics are chaotic, generally present both discrete and continuous symmetries. In this paper, we explain how these properties must be taken into account in order to obtain the proper (i.e., symmetry projected) $\ensuremath{\hbar}$ expansion of semiclassical expressions like the Gutzwiller trace formula. In the case of the hydrogen atom in a magnetic field, we shed light on the excellent agreement between present theory and exact quantum results.
B. G. C. Lackenby - One of the best experts on this subject based on the ideXlab platform.
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Calculation of Atomic Spectra and transition amplitudes for the superheavy element Db (Z =105)
Physical Review A, 2018Co-Authors: B. G. C. Lackenby, V. A. Dzuba, Victor V. FlambaumAbstract:Atomic Spectra and other properties of superheavy element dubnium (Db, Z=105) are calculated using recently developed method combining configuration interaction with perturbation theory (the CIPT method, Dzuba et al, Phys. Rev. A, {\bf 95}, 012503 (2017)). These include energy levels for low-lying states of Db and Db~II, electric dipole transition amplitudes from the ground state of Db, isotope shift for these transitions and ionisation potential of Db. Similar calculations for Ta, which is lighter analog of Db, are performed to control the accuracy of the calculations.
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calculation of Atomic Spectra and transition amplitudes for the superheavy element db z 105
Physical Review A, 2018Co-Authors: B. G. C. Lackenby, V. A. Dzuba, Victor V. FlambaumAbstract:Atomic Spectra and other properties of superheavy element dubnium (Db, Z=105) are calculated using recently developed method combining configuration interaction with perturbation theory (the CIPT method, Dzuba et al, Phys. Rev. A, {\bf 95}, 012503 (2017)). These include energy levels for low-lying states of Db and Db~II, electric dipole transition amplitudes from the ground state of Db, isotope shift for these transitions and ionisation potential of Db. Similar calculations for Ta, which is lighter analog of Db, are performed to control the accuracy of the calculations.
S. G. Zemlyanoi - One of the best experts on this subject based on the ideXlab platform.
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Hyperfine magnetic anomaly in the Atomic Spectra of rare-earth elements
Optics and Spectroscopy, 2002Co-Authors: Yu. P. Gangrskiĭ, S. G. Zemlyanoi, D. V. Karaivanov, N. N. Kolesnikov, K. P. Marinova, B. N. Markov, V. S. RostovskiiAbstract:Hyperfine-splitting constants in the optical Spectra of rare-earth elements, Nd, Eu, Gd, and Lu, were measured using the laser-induced resonance fluorescence in a low-divergence Atomic beam. Values of the hyperfine magnetic anomaly for different Atomic levels were determined by comparing the ratios of the magnetic dipole constants of neighboring isotopes with odd numbers of protons or neutrons. The relation of these values to the special features of the Atomic and nuclear structure of the investigated elements is discussed.
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Hyperfine magnetic anomaly in Atomic Spectra of rare-earth elements
Hyperfine Interactions, 2001Co-Authors: Yu. P. Gangrsky, K. P. Marinova, D. V. Karaivanov, B. N. Markov, S. G. ZemlyanoiAbstract:The constants of the hyperfine splitting in the Atomic optical Spectra of the rare-earth elements - Nd, Eu, Gd and Lu - were measured. The method of laser resonance fluorescence in the parallel Atomic beam was used. The values of the hyperfine magnetic anomaly were determined from the comparision of magnetic dipole constant ratios of the neighbouring odd Z or N isotopes for the different Atomic levels. The connection of these values and the parameters of Atomic and nuclear structure is discussed.
Jean-christophe Pain - One of the best experts on this subject based on the ideXlab platform.
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Detailed computation of hot-plasma Atomic Spectra
Laser and Particle Beams, 2015Co-Authors: Jean-christophe Pain, Franck Gilleron, Thomas BlenskiAbstract:AbstractWe present recent evolutions of the detailed opacity code SCO-RCG which combines statistical modelings of levels and lines with fine-structure calculations. The code now includes the Partially Resolved Transition Array model, which allows one to replace a complex transition array by a small-scale detailed calculation preserving energy and variance of the genuine transition array and yielding improved higher-order moments. An approximate method for studying the impact of strong magnetic field on opacity and emissivity was also recently implemented. The Zeeman line profile is modeled by fourth-order Gram-Charlier expansion series, which is a Gaussian multiplied by a linear combination of Hermite polynomials. Electron collisional line broadening is often modeled by a Lorentzian function and one has to calculate the convolution of a Lorentzian with Gram-Charlier distribution for a huge number of Spectral lines. Since the numerical cost of the direct convolution would be prohibitive, we propose, to obtain the resulting profile, a fast and precise algorithm, relying on a representation of the Gaussian by cubic splines.
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Random-matrix theory and complex Atomic Spectra
arXiv: Atomic Physics, 2012Co-Authors: Jean-christophe PainAbstract:Around 1950, Wigner introduced the idea of modelling physical reality with an ensemble of random matrices while studying the energy levels of heavy Atomic nuclei. Since then, the field of random-matrix theory has grown tremendously, with applications ranging from fluctuations on the economic markets to complex Atomic Spectra. The purpose of this short article is to review several attempts to apply the basic concepts of random-matrix theory to the structure and radiative transitions of atoms and ions, using the random matrices originally introduced by Wigner in the framework of the gaussian orthogonal ensemble. Some intrinsic properties of complex-atom physics, which could be enlightened by random-matrix theory, are presented.
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Statistics of electric-quadrupole lines in Atomic Spectra
Journal of Physics B: Atomic Molecular and Optical Physics, 2012Co-Authors: Jean-christophe Pain, Franck Gilleron, Jacques Bauche, Claire Bauche-arnoultAbstract:In hot plasmas, a temperature of a few tens of eV is sufficient for producing highly stripped ions where multipole transitions become important. At low density, the transitions from tightly bound inner shells lead to electric-quadrupole (E2) lines which are comparable in strength with electric-dipole ones. In this work, we propose analytical formulas for the estimation of the number of E2 lines in a transition array. Such expressions rely on statistical descriptions of electron states and J-levels. A generalized ‘J-file’ sum rule for E2 lines and the strength-weighted shift and variance of the line energies of a transition array nlN + 1 → nlNn′l′ of inter-configuration E2 lines are also presented.
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Characterization of anomalous Zeeman patterns in complex Atomic Spectra
Physical Review A, 2012Co-Authors: Jean-christophe Pain, Franck GilleronAbstract:The modeling of complex Atomic Spectra is a difficult task, due to the huge number of levels and lines involved. In the presence of a magnetic field, the computation becomes even more difficult. The anomalous Zeeman pattern is a superposition of many absorption or emission profiles with different Zeeman relative strengths, shifts, widths, asymmetries and sharpnesses. We propose a statistical approach to study the effect of a magnetic field on the broadening of Spectral lines and transition arrays in Atomic Spectra. In this model, the sigma and pi profiles are described using the moments of the Zeeman components, which depend on quantum numbers and Land\'{e} factors. A graphical calculation of these moments, together with a statistical modeling of Zeeman profiles as expansions in terms of Hermite polynomials are presented. It is shown that the procedure is more efficient, in terms of convergence and validity range, than the Taylor-series expansion in powers of the magnetic field which was suggested in the past. Finally, a simple approximate method to estimate the contribution of a magnetic field to the width of transition arrays is proposed. It relies on our recently published recursive technique for the numbering of LS-terms of an arbitrary configuration.
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Benford's law and complex Atomic Spectra.
Physical review. E Statistical nonlinear and soft matter physics, 2008Co-Authors: Jean-christophe PainAbstract:We found that in transition arrays of complex Atomic Spectra, the strengths of electric-dipolar lines obey Benford's law, which means that their significant digits follow a logarithmic distribution favoring the smallest values. This indicates that Atomic processes result from the superposition of uncorrelated probability laws and that the occurrence of digits reflects the constraints induced by the selection rules. Furthermore, Benford' law can be a useful test of theoretical spectroscopic models. Its applicability to the statistics of electric-dipolar lines can be understood in the framework of random matrix theory and is consistent with the Porter-Thomas law.