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1

Radiative Lifetimes of Rydberg States in Neutral Gallium

100%

Yildiz M., Çelık G., Kiliç H.

Acta Physica Polonica A

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2009

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vol. 115

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issue 3

641-646

EN

Radiative lifetimes were calculated using weakest bound electron potential model theory for 4s^{2} ns ^{2}S_{1/2} (n ≥ 7), 4s^{2} np ^{2}P^{0}_{1/2} (n ≥ 5), 4s^{2} np ^{2}P ^{0}_{3/2} (n ≥ 6), 4s^{2} nd ^{2}D^{0}_{3/2} (n ≥ 6), 4s^{2} nd ^{2}D ^{0}_{5/2} (n ≥ 6) series in neutral gallium. The use of the quantum defect theory and Martin's expressions allowed us to supply lifetime values along by means of the series above. The results obtained in this work presented good agreement with theoretical and experimental values. Moreover, some lifetime values not existing in the literature for highly excited Rydberg states in gallium atom were obtained using this method.

2

Spectral Intensities for the Emission |^4S_{3/2}Γ_8〉 → |^4I_{15/2}Γ〉in the Cs_2NaErCl_6

100%

Acevedo R., Soto-Bubert A., Navarro G., Meruane T., Stręk W.

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issue 3

233-251

EN

We report explicit vibronic intensity calculations for the |^4S_{3/2}Γ_8> → |^4I_{15/2}Γ>excitations in the Cs_2NaErCl_6 elpasolite-type systems, based upon new and updated experimental data, obtained from optical absorption measurements made at 10 K, in the energy range from 6,000 up to 26,000 cm^{-1}. Our calculation model is a generalization of the vibronic crystal field-ligand polarization method and the calculation is performed using a minimum set of adjustable parameters - all and each of them have a clear physical meaning. Our strategy was chosen so as to make a significant distinction with previous calculations, performed by other authors, who have worked out a model originated from a supra-parameterized scheme, within the framework of the superposition model of Newman. Throughout the course of the current work, it is shown that our model is suitable to handle this kind of calculations and also that the numerical results obtained are in fairly good agreement with experiment.

3

Analysis of Line Strength Data for the Spectra οf C(I), N(II), N(I) and O(II)

63%

Bacławski A., Musielok J.

Acta Physica Polonica A

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2009

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vol. 116

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issue 2

176-184

EN

Recently determined experimental and theoretical data on line strengths within 3s-3p and 3p-3d multiplets for C(I), N(II), N(I) and O(II) are analyzed. An overall satisfactory agreement between experimental data and results of recent sophisticated calculations is found with exception of only some weaker transitions. However, the measured and calculated relative line strengths disagree significantly with data resulting from the LS coupling scheme, particularly for 3p-3d transitions. In numerous cases these differences are - to a considerable degree - "regular" along the isoelectronic sequences C(I)-N(II) and N(I)-O(II). For some multiplets these discrepancies also correlate with departures from the Landé interval rule for terms involved in the corresponding transitions.

4

Oscillator Strengths for Allowed Transitions in Li(II)

63%

Ateş Ş., Çelik G.

Acta Physica Polonica A

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2009

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vol. 116

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issue 2

169-175

EN

Electric dipole oscillator strengths have been computed for transitions between both multiplet and individual lines in the Li(II) ion. The weakest bound electron potential model theory has been used. We have employed both numerical Coulomb approximation wave functions and numerical non-relativistic Hartree-Fock wave functions in the determination of expectation values of radii. The necessary energy values have been taken from experimental ionization energies. The oscillator strengths calculated with parameters obtained by using the two different wave functions have been compared not only to each other but also to other data taken from literature. A good agreement with results in literature has been obtained.

5

Regularities of Line Strengths in Spectra of NI, FI, and NeII

63%

Musielok J.

Acta Physica Polonica A

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1998

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vol. 94

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issue 1

13-23

EN

Recently experimentally determined individual (fine structure) line strengths for the spectra of NI, FI, and NeII are analysed, searching for regularities resulting from similarities in the structure of these species. Strengths of spectral lines of the prominent 3s-3p and 3p-3d transition arrays are investigated. The absolute scales of these experimentally derived data are based on independently determined lifetimes for excited levels of NI, FI, and NeII. The simple Coulomb approximation method was applied for calculations of the matrix elements for the "jumping" electron in order to obtain an average trend in line strengths of the studied emitters. In the case of the isoelectronic species (FI, NeII), additionally the trend resulting from the perturbation theory is taken for comparison. Except the trend study of the absolute scale, the strengths of individual lines within analogous multiplets (in a relative scale) are investigated and compared with data resulting from LS coupling scheme and with semi-empirical calculations.

6

Radiative Lifetimes for Singly Ionized Beryllium

63%

Çelik G., Atalay B., Ateş Ş.

Acta Physica Polonica A

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2016

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vol. 130

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issue 3

705-709

EN

The theoretical lifetimes for singly ionized beryllium (Be II) have been calculated using the weakest bound electron potential model theory and the quantum defect orbital theory under the assumption of the LS coupling scheme. In the calculations, many states are considered. Some lifetime values for highly excited levels have been obtained using these methods. The lifetimes presented in this work have been compared with the early theoretical calculations and measurements presented in the literature. A good agreement with the results in the literature has been obtained.

7

Core Polarization Effects in the Relativistic Quantum-Defect-Orbital Theory

63%

Bielińska-Wąż D., Martin I., Karwowski J.

Acta Physica Polonica A

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1994

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vol. 85

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issue 5

805-812

EN

The quantum-defect-orbital method has been reformulated in order to include both relativistic effects and the electron correlation described by a core polarization potential. All quantities appearing in this formulation may be evaluated analytically. A comparison with experimental results demonstrates, on one hand, significance of the relativity-correlation corrections and, on the other, inadequacy of the relativistic quantum-defect-orbital approach when indirect relativistic effects are important, i.e. when atoms contain closed shells of d electrons.

8

The Emission Spectra for the Cs_2NaScCl_6:MoCl_6^{3-} System in the Fm3m Space Group

63%

Acevedo R., Meruane T., Navarro G.

Acta Physica Polonica A

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2001

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vol. 99

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issue 2

233-242

EN

On the basis of the data reported by Flint and Paulusz, we have undertaken a theoretical investigation of the intensity mechanism for the various emissions:Γ_8(^2T_{2g} ) → Γ_8(^4A_{2g}), Γ_8(^2E_{g}), Γ_8(^2T_{1g}), Γ_6(^2T_{1g}) for the Cs_2NaScCl_6:MoCl_6^{3-} system in the Fm3m-space group. The experimental data available refer to the visible and near infrared luminescence spectra of MoCl_6^{3-} complex ion in different hosts, such as Cs_2NaMCl_6 (M = Sc, Y, In), measured between 15,000 cm^{-1} and 3,000 cm^{-1} at liquid helium temperatures. At least, five luminescence transitions have been identified and assigned and each of them show extensive vibronic structure. A careful analysis of this experimental data shows that for the various observed electronic transitions, the vibrational frequencies change only slightly, and therefore there is no indication that the system undergoes both a significant and relevant Jahn-Teller distortion (along an active coordinate). There is however clear evidence that for the chloro-elpasolites, there is a strong resonance interaction between ν_3(τ_{1u} : stretching) of the MoX_6^{3-}, complex ion and that of the host when M = In, Y. Thus for M = Sc, the slighter higher host ν_3, wave number is likely to minimize the effect of this coupling. This evidence will allow us for the Cs_2NaScCl_6:MoCl_6^{3-} system to neglect, in the first-order approximation, the coupling among the internal and the external vibrations and to proceed using a both a molecular and the independent system models.

9

Ligand-Framework Coupling Vibrations. The ^2E_g → ^4A_{2g} Transition in the Cr(CN)_6^{3-} Complex Ion

63%

Acevedo R., Passman M., Navarro G.

Acta Physica Polonica A

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2001

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vol. 99

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issue 2

215-232

EN

In this research paper we examine the role played by the bending vibrational modes of motion, δ(Cr-C-N) to influence the observed overall and relative vibronic intensity distribution for the ^2E_g → ^4A_{2g} phosphorescence of the Cr(CN)_6^{3-} complex ion. The calculation was carried out assuming both: (a) a seven-atom system model (molecular approximation) and (b) a negligible distortion from the octahedral symmetry for the system. The ligand polarization formalism was employed with reference to this system, since the ligand subsystems (CN)^{-1} are highly polarizable and as a consequence a conventional crystal field calculation would be both unrealistic and unappropriate. This system was chosen since there is a solid evidence to conclude that vibrations of the same type in the τ_{1u} and τ_{2u} symmetry blocks induce comparable intensity. This is a clear indication that both the τ_{1u} and τ_{2u}: δ(Cr-C-N) bending vibrations are exceptionally efficient to promote this radiative transition. This dynamical model is tested against the experimental data and it is shown that the model calculation, though approximate, gives results in excellent agreement with experiment.

10

Branching Ratio Measurements for Ge I and Ge II

63%

Bratasz Ł., Musioł K.

Acta Physica Polonica A

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2000

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vol. 98

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issue 4

345-351

EN

A high resolution Fourier-transform spectrometer was used to measure branching ratios for 5s-5p, 4d-6s, 6s-6p, 5s-6p, 4d-6p, 4d-7p transitions in neutral germanium and 4d-4f, 4p^{2}-4f, 4p^{2}-5p, 5s-5p, 4p^{2}-4p, 4d-6p, 4p^{2}-6p, 4d-5f, 4p^{2}-5f, 4d-7p, 4p^{2}-7p of singly ionized germanium. Measurements were performed with a hollow cathode as a light source. Spectral lines intensities were measured in a spectral range from 200 to 3500 nm. Absolute transition probabilities for some Ge II lines were obtained using experimental lifetime values for the 4s^{2}4f^{2}F_{5/2},^{2}F_{7/2} and 4s^{2}5p^{2}P_{1/2},^{2}P_{3/2} levels. Our results for transitions in neutral germanium show that some infrared lines, so far overlooked in spectral analyses, give a strong contribution to Ge spectrum. Our transition probabilities obtained for Ge II lines are lower than all other experimental and theoretical results, in one case even by an order of magnitude.

11

Transition Parameters for Doubly Ionized Lutetium

51%

Karaçoban B., Özdemír L.

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EN

Using the relativistic Hartree-Fock method developed by Cowan, we calculated the electric dipole (E1) transition parameters such as the wavelengths, the weighted oscillator strengths, and the transition probabilities (or rates) for doubly ionized lutetium (Lu III, Z=71). We compared the results with available calculations and experiments in literature. A discussion of these calculations for Lu III in this study has also been made in view of the relativistic Hartree-Fock method.

12

Electric Dipole Transition Parameters for Low-Lying Levels for Neutral Actinium

51%

Özdemır L., Ürer G.

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issue 4

563-569

EN

We have calculated the energies of some low-lying levels (6d7s^2, 6d^2 7s, 6d7s7p and 6d^27p) and electric dipole transition parameters (wavelengths, oscillator strengths and transition probabilities) between them for neutral actinium (Z=89). In the calculations, the correlation and relativistic effects are considered by multiconfiguration Hartree-Fock method within the framework Breit-Pauli Hamiltonian. The results obtained are compared with the available experimental and theoretical works in the literature.

13

Energies and Radiative Transition Parameters for Mg-Like Tungsten

51%

Özdemír L., Günday Konan G., Kabakçi S.

Acta Physica Polonica A

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2013

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vol. 124

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issue 4

649-657

EN

By applying AUTOSTRUCTURE code, the energies and transitions for allowed (E1) and forbidden (E2, M1, and M2) lines for low-lying configurations in magnesium-like tungsten (W^{62+}) are studied. The electron correlation and relativistic effects are included in computations. Good agreement between our results and available other results are found. The data for E2, M1 and M2 besides some E1 transitions for low-lying levels are presented for the first time.

14

Blackbody-Radiation-Induced Decay and Excitation οf Rydberg States in Sodium

51%

Ovsiannikov V., Glukhov I.

Acta Physica Polonica A

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2009

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vol. 116

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issue 4

528-531

EN

Rates of the blackbody radiation-induced excitation and decay were calculated for the S-, P-, D-series of the Rydberg states in sodium atoms with the Fues model potential method. Comparisons between three branches of the state depopulation mechanism (spontaneous decays, blakbody radiation-induced and excitations) were carried out. Simple analytical formulas were proposed for ratios of the blackbody radiation-induced decay and excitation rates to the spontaneous decay rate.

15

Calculations of the Atomic Structure for Fe XVII Lines

51%

Zhou C., Cao J.-J., Liang L., Yu G.-H., Wang Z.-M., He H.-Y.

Acta Physica Polonica A

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2016

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vol. 129

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issue 6

1109-1117

EN

Energy levels, line strengths, oscillator strengths, radiative decay rates and fine structure collision strengths are presented for sixteen-times ionized iron (Fe XVII). The atomic data are calculated with the AUTOSTRUCTURE code, where relativistic corrections are introduced according to the Breit-Pauli distorted wave approach. The calculations of atomic data for 89 fine-structure levels generated from eleven configurations 2s²2p⁶, 2s²2p⁵ (3s, 3p, 3d), 2s²2p⁵ (4s, 4p, 4d, 4f) and 2s¹2p⁶ (3s, 3p, 3d) of the Ne-like Fe ion are presented. Fine structure collision strengths for transitions from the ground and the first four excited levels are presented at four electron energies: 75, 125, 175, and 250 Ry. These atomic structure data are compared with the available experimental and theoretical results.

16

Transition Probabilities and Oscillator Strengths for E1 Transitions of Ce III

51%

Karaçoban Usta B.

Acta Physica Polonica A

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2015

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vol. 127

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issue 6

1605-1616

EN

We report calculations of wavelengths, oscillator strengths, and transition probabilities (or rates) for electric dipole (E1) transitions in doubly ionized cerium (Ce III, Z=58), using the relativistic Hartree-Fock method developed by Cowan. Comparisons are made with the previously reported available calculations and experiments in literature.

17

Long-Range Interactions and the Oscillator Strength for the 1_u, 0^+_u → X 0^+_g Transitions in Zn_2

45%

Kubkowska M., Szczęśniak T., Grycuk T.

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issue 4

317-328

EN

The interaction potentials for Zn_2 electronic states {1}_u and {0}_u^+ correlated with (4 {1}^P_1+4 {1}^S_0) asymptote in the long-range region (10-25) Å and the oscillator strength f for the absorption transition to these states are derived experimentally from a careful analysis of the self-broadened resonance 213.8 nm line of Zn. It is found that although the interatomic interactions at so long distances are dominated by resonance potential of the form C_3/R^3 resulting in the Lorentzian line shape, the parameter C_3 and thus f value significantly decrease with R decreasing. This effect proved to be a linear function of R^{-1} yielding the oscillator strength for the considered line f_0=1.456 ± 0.010 from R → ∞ extrapolation. This value seems to be the most accurate experimental result as yet and shows that the best theoretical values for this quantity are overestimated. It is suggested that the long-range behaviour of the potential energy curves observed here for the first time represents the effective potentials including dominating resonance interactions and a possible slight contribution of the dispersion interactions as well as the R-dependent spin-orbit interaction.

18

Energies and Lifetimes for Some Excited Levels in La I

45%

Karaçoban B., Özdemir L.

Acta Physica Polonica A

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2008

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vol. 113

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issue 6

1609-1618

EN

We calculated relativistic energies and Landéfactors for 5d6s², 5d²6s, 5d³, 5d6s7s, 4f6s6p, 5d6s6p, 5d²6p, and 4f5d6s levels in neutral lanthanum (Z=57). We also obtained electric dipole transition energies and lifetimes for some excited levels. The calculations are based upon the multiconfiguration Hartree-Fock method within the framework Breit-Pauli relativistic corrections. Moreover, the results obtained were compared with other calculations and experiments.

19

Electric Dipole Transition Parameters for 5s-5p and 5p-5d Transitions in Doubly Ionized Xenon

45%

Eser S., Özdemir L.

Acta Physica Polonica A

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2017

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vol. 132

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issue 4

1284-1289

EN

Using the general-purpose relativistic atomic structure package based on the fully relativistic multiconfiguration Dirac-Fock method, we have reported the electric dipole transition (E1) parameters such as wavelengths, weighted oscillator strengths, transition rates (or probabilities) and line strengths for 5s-5p and 5p-5d transitions in Xe²⁺. In calculations, the Breit interaction and quantum electrodynamic effects have been included as perturbations. The calculated values for energy levels including valence and core-valence correlation have been compared with other available experimental and theoretical values in literature. Our transition results can provide useful data for, in particular, experimental works in future.

Refine search results

Radiative Lifetimes of Rydberg States in Neutral Gallium

Spectral Intensities for the Emission |^4S_{3/2}Γ_8〉 → |^4I_{15/2}Γ〉in the Cs_2NaErCl_6

Analysis of Line Strength Data for the Spectra οf C(I), N(II), N(I) and O(II)

Oscillator Strengths for Allowed Transitions in Li(II)

Regularities of Line Strengths in Spectra of NI, FI, and NeII

Radiative Lifetimes for Singly Ionized Beryllium

Core Polarization Effects in the Relativistic Quantum-Defect-Orbital Theory

The Emission Spectra for the Cs_2NaScCl_6:MoCl_6^{3-} System in the Fm3m Space Group

Ligand-Framework Coupling Vibrations. The ^2E_g → ^4A_{2g} Transition in the Cr(CN)_6^{3-} Complex Ion

Branching Ratio Measurements for Ge I and Ge II

Transition Parameters for Doubly Ionized Lutetium

Electric Dipole Transition Parameters for Low-Lying Levels for Neutral Actinium

Energies and Radiative Transition Parameters for Mg-Like Tungsten

Blackbody-Radiation-Induced Decay and Excitation οf Rydberg States in Sodium

Calculations of the Atomic Structure for Fe XVII Lines

Transition Probabilities and Oscillator Strengths for E1 Transitions of Ce III

Long-Range Interactions and the Oscillator Strength for the 1_u, 0^+_u → X 0^+_g Transitions in Zn_2

Energies and Lifetimes for Some Excited Levels in La I

Electric Dipole Transition Parameters for 5s-5p and 5p-5d Transitions in Doubly Ionized Xenon