R-matrix calculations of photoionization cross section of Ne-like tungsten

2015 ◽  
Vol 93 (11) ◽  
pp. 1221-1226 ◽  
Author(s):  
Indu Khatri ◽  
Arun Goyal ◽  
Sunny Aggarwal ◽  
A.K. Singh ◽  
Man Mohan
Keyword(s):  
Cross Section ◽  
Energy Levels ◽  
Resonance Energy ◽  
Photoionization Cross Section ◽  
Distorted Wave ◽  
Rydberg Series ◽  
Close Coupling ◽  
R Matrix ◽  
Coupling Approximation ◽  
Wave Methods

The photoionization cross section calculation for the ground state 1s22s22p6 1S (J = 0) of Ne-like W64+ has been performed in the close-coupling approximation using the Dirac–Coulomb R-matrix method. The resonance structures are analysed and described by finding the resonance energy positions of prominent Rydberg series 2s2p6(2S)np 1P0 for W LXV ion. To calculate fine structure energy levels, multi-configuration Dirac–Fock and relativistic distorted-wave methods have been employed. Wherever possible we have compared our work with the available data. The present results will be useful for diagnostics and modeling of plasma in ITER and other fusion devices.

Photoionization of Al X from ground state using the relativistic R-matrix close-coupling method

2014 ◽  
Vol 92 (3) ◽  
pp. 241-245 ◽  
Author(s):  
Liang Liang ◽  
Xu-yang Liu ◽  
Chao Zhou
Keyword(s):  
Cross Sections ◽  
Ground State ◽  
Energy Levels ◽  
Resonance Energy ◽  
Photoionization Cross Section ◽  
Rydberg Series ◽  
Close Coupling ◽  
R Matrix ◽  
Target States ◽  
Distorted Wave Method

The relativistic R-matrix method is used to calculate the total photoionization cross sections from the ground state 1s22s2 1S0 of Al X for photon energies ranges from the first ionization threshold to just above the eighth threshold of the residual ion Al XI. In this work, the relativistic distorted-wave method is employed to calculate the fine-structure energy levels and radial functions. The lowest eight level target states of Al XI are used in the photoionization calculations of Al X and should provide a reasonably complete database for practical application for photoionization cross section for Al X. The resonance energy levels and widths of 18 Rydberg series have been investigated.

Photoionization of Cl-like Ni XII using relativistic R-matrix close-coupling method

2017 ◽  
Vol 95 (11) ◽  
pp. 1136-1141
Author(s):  
Indu Khatri ◽  
Arun Goyal ◽  
A.K. Singh ◽  
Narendra Singh ◽  
Man Mohan
Keyword(s):  
National Laboratory ◽  
Energy Levels ◽  
Resonance Energy ◽  
Rydberg Series ◽  
Interaction Technique ◽  
Close Coupling ◽  
Nickel Ions ◽  
R Matrix ◽  
Target States ◽  
Ionic States

In this study, photoionization (PI) of nickel ions Ni XII is performed using the relativistic close-coupling Breit–Pauli R-matrix method. The calculation includes 47 lowest target states of Ni XIII, which have been evaluated using a sophisticated configuration interaction technique. Results for the PI of the ground state 3s23p5 (2[Formula: see text]) and first excited state 3s23p5 (2[Formula: see text]) are provided. The PI of this Cl-like ion is characterized by multiple Rydberg series of autoionizing resonances converging to various ionic states of Ni XIII. Our background cross section agrees well with that obtained using the Los Almos National Laboratory PI code. The resonance energy levels and widths of the Rydberg series are presented using the Quigley and Berrington approach. We believe that our results will be useful for astrophysical plasma research.

scholarly journals Photoionization Cross-Sections of Carbon-Like N+ Near the K-Edge (390–440 eV)

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 27
Author(s):  
Jean-Paul Mosnier ◽  
Eugene T. Kennedy ◽  
Jean-Marc Bizau ◽  
Denis Cubaynes ◽  
Ségolène Guilbaud ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
Cross Sections ◽  
Experimental Studies ◽  
Photoionization Cross Section ◽  
Theoretical Work ◽  
Rydberg Series ◽  
R Matrix ◽  
Resonance Strengths ◽  
Nitrogen Ion

High-resolution K-shell photoionization cross-sections for the C-like atomic nitrogen ion (N+) are reported in the 398 eV (31.15 Å) to 450 eV (27.55 Å) energy (wavelength) range. The results were obtained from absolute ion-yield measurements using the SOLEIL synchrotron radiation facility for spectral bandpasses of 65 meV or 250 meV. In the photon energy region 398–403 eV, 1s⟶2p autoionizing resonance states dominated the cross section spectrum. Analyses of the experimental profiles yielded resonance strengths and Auger widths. In the 415–440 eV photon region 1s⟶(1s2s22p2 4P)np and 1s⟶(1s2s22p2 2P)np resonances forming well-developed Rydberg series up n=7 and n=8 , respectively, were identified in both the single and double ionization spectra. Theoretical photoionization cross-section calculations, performed using the R-matrix plus pseudo-states (RMPS) method and the multiconfiguration Dirac-Fock (MCDF) approach were bench marked against these high-resolution experimental results. Comparison of the state-of-the-art theoretical work with the experimental studies allowed the identification of new resonance features. Resonance strengths, energies and Auger widths (where available) are compared quantitatively with the theoretical values. Contributions from excited metastable states of the N+ ions were carefully considered throughout.

scholarly journals Photoionization Cross Sections of Carbon-Like N+ near the K-Edge (390 eV - 440 eV)

2021 ◽  
Author(s):  
Jean-Paul Mosnier ◽  
Eugene T Kennedy ◽  
Jean-Marc Bizau ◽  
Denis Cubaynes ◽  
Ségolène Guilbaud ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
Cross Sections ◽  
Experimental Studies ◽  
Photoionization Cross Section ◽  
Theoretical Work ◽  
Rydberg Series ◽  
R Matrix ◽  
Resonance Strengths ◽  
Nitrogen Ion

High-resolution K-shell photoionization cross-sections for the C-like atomic nitrogen ion (N+) are reported in the 398 eV (31.15 Å) to 450 eV (27.55 Å) energy (wavelength) range. The results were obtained from absolute ion-yield measurements using the SOLEIL synchrotron radiation facility for spectral bandpasses of 65 meV or 250 meV. In the photon energy region 398 eV - 403 eV, 1s⟶2p autoionizing resonance states dominated the cross section spectrum. Analyses of the experimental profiles yielded resonance strengths and Auger widths. In the 415 eV - 440 eV photon region 1s⟶1s2s22p2 4Pnp and 1s⟶1s2s22p2 2Pnp resonances forming well-developed Rydberg series up n=7 and n=8 , respectively, were identified in both the single and double ionization spectra. Theoretical photoionization cross-section calculations, performed using the R-matrix plus pseudo-states (RMPS) method and the multiconfiguration Dirac-Fock (MCDF) approach were bench marked against these high-resolution experimental results. Comparison of the state-of-the-art theoretical work with the experimental studies allowed the identification of new resonance features. Resonance strengths, energies and Auger widths (where available) are compared quantitatively with the theoretical values. Contributions from excited metastable states of the N+ ions were carefully considered throughout.

scholarly journals Collisional Excitation of Fluorine Like Tungsten using Relativistic Dirac Atomic R-matrix Method

2015 ◽  
Vol 2 (1) ◽  
pp. 1-14
Author(s):  
Arun Goyal ◽  
Indu Khatri ◽  
Sunny Aggarwal ◽  
A. K. Singh ◽  
Rinku Sharma ◽  
...  
Keyword(s):  
Fine Structure ◽  
Energy Levels ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Collisional Excitation ◽  
Distorted Wave ◽  
Fusion Plasma ◽  
R Matrix ◽  
Target States ◽  
Effective Collision

We report the new extensive calculations for collision strengths and effective collision strengths of Electron impact excitation of fine structure transitions in F-like W using fully relativistic Dirac Atomic R-matrix Code. We have included all 113 target states which belong to 2s22p5, 2s2p6, 2s22p43l, 2s2p53l, 2p63l configurations. The convergence of reported collision strengths is tested by performingthe same calculations for lesser number of target states which verify the individuality of our results.Effective collision strengthsover a wide temperature range 104-107K are computed. Further, to assess the accuracy and authenticity of our target states energies, a similar parallel calculation has also been performed using a fully relativistic distorted wave (RDW) method and a comparison of energy levels with NIST, FAC and other experimental observations has been made. We believe that the collision strength results for all forbidden transitions within the 113 fine structure levels, presented in this paper will play a substantial role in fusion plasma diagnostics.

1s hole excited states of Be: partial autoionization rates compared with recent experimental data

1991 ◽  
Vol 69 (5) ◽  
pp. 603-605
Author(s):  
D. Petrini ◽  
J. A. Tully
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Cross Section ◽  
Ground State ◽  
Photoionization Cross Section ◽  
Recent Experimental Data ◽  
Auger Decay ◽  
Close Coupling ◽  
University College London ◽  
The University

Auger decay following inner-shell photoexcitation of atomic beryllium is studied using the University College London close-coupling codes. We reproduce some of the features observed experimentally by Krause and co-workers. The vastly predominant decay mode of Be 1s2s2np1P° is to Be+ 1s2np rather than the ground state of Be+ and the theoretical np/2s ratio agrees with the experimental value. The peak observed in the partial photoionization cross section for formation of 1s(2s2p3P) 2P° is due to photoexcitation of 1s2s(3s3p3P) 1P° followed by autoionization. Our theoretical result reproduces this feature. Strong configuration interaction effects limit the accuracy we can achieve for the radiationless decay width.

scholarly journals Absolute high-resolution Se+photoionization cross-section measurements with Rydberg-series analysis

2011 ◽  
Vol 84 (1) ◽  
Author(s):  
D. A. Esteves ◽  
R. C. Bilodeau ◽  
N. C. Sterling ◽  
R. A. Phaneuf ◽  
A. L. D. Kilcoyne ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
Photoionization Cross Section ◽  
Rydberg Series ◽  
Series Analysis
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