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.

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.

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.

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.

scholarly journals Partial Photoionization Cross Sections of Chromium from the Ground and Excited States

Atoms ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 51
Author(s):  
Oleg Zatsarinny ◽  
Swaraj Tayal
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Bound States ◽  
Close Coupling ◽  
R Matrix ◽  
Hartree Fock ◽  
Nonresonant Background ◽  
Ionic States ◽  
Matrix Calculation

Partial and total photoionization cross sections of iron-peak elements are important for the determination of abundances in late-type stars and nebular objects. We have investigated photoionization of neutral chromium from the ground and excited states in the low energy region from the first ionization threshold at 6.77 eV to 30 eV. Accurate descriptions of the initial bound states of Cr I and the final residual Cr II ionic states have been obtained in the multiconfiguration Hartree-Fock method together with adjustable configuration expansions and term-dependent non-orthogonal orbitals. The B-spline R-matrix method has been used for the calculation of photoionization cross sections. The 194 LS final ionic states of Cr II 3d44s, 3d34s2, 3d5, 3d44p, and 3d34s4p principal configurations have been included in the close-coupling expansion. The inclusion of all terms of these configurations has significant impact on the near-threshold resonance structures as well as on the nonresonant background cross sections. Total photoionization cross sections from the ground 3d54sa7S and excited 3d54sa5S, 3d44s2a5D, 3d54pz5P, and 3d44s4py5P states of Cr I have been compared with other available R-matrix calculation to estimate the likely uncertainties in photoionization cross sections. We analyzed the partial photoionization cross sections for leaving the residual ion in various states to identify the important scattering channels, and noted that 3d electron ionization channel becomes dominant at higher energies.

scholarly journals Investigation of dominant states for dielectronic recombination in short-pulse laser-produced aluminum plasma

2012 ◽  
Vol 31 (1) ◽  
pp. 1-8 ◽  
Author(s):  
V. Stancalie
Keyword(s):  
Pulse Laser ◽  
Short Pulse ◽  
Energy Levels ◽  
Resonance Energy ◽  
Dielectronic Recombination ◽  
General Purpose ◽  
Detailed Calculation ◽  
Close Coupling ◽  
Short Pulse Laser ◽  
Aluminum Plasma

AbstractThis paper presents the results of relativistic calculation intended specifically to investigate the dominant states for dielectronic recombination of Li-like into Be-like Al ions in short-pulse laser produced plasmas. The relativistic Dirac R-matrix calculation is performed to output resonance energy levels and rates. The target energies and orbitals are calculated with the extended average level multi-configurational Dirac-Fock method in the general-purpose relativistic atomic structure package. This type of calculation gives a set of 13 bound orbitals that is optimized over all the levels included. The resulting 13 relativistic orbitals produced 74 Jπ levels, all of which are to be used in the close-coupling expansion. To the best of our knowledge, the work reported herein describes for the first time such detailed calculation for this atomic system and the results are relevant to the short-pulse laser produced plasma modeling.

Photoionization of Al-like Si using the R-matrix method

2011 ◽  
Vol 89 (11) ◽  
pp. 1119-1126 ◽  
Author(s):  
Jagjit Singh ◽  
Sunny Aggarwal ◽  
A.K.S. Jha ◽  
A.K. Singh ◽  
M. Mohan
Keyword(s):  
Cross Sections ◽  
Matrix Method ◽  
Relativistic Effects ◽  
Coupling Scheme ◽  
Rydberg Series ◽  
Channel Coupling ◽  
R Matrix ◽  
Practical Applications ◽  
Physical Effects ◽  
Ionic States

Relativistic calculations are made for photoionization of the ground state 3s23p ([Formula: see text]) and the lowest six excited states 3s23p ([Formula: see text]), 3s3p2 (4P1/2,3/2,5/2), and 3s3p2 (2D3/2,5/2) of Al-like Si, using the Breit–Pauli Hamiltonian within the R-matrix method. Cross sections are determined by the Rydberg series of autoionizing resonances converging to various ionic states. Relativistic effects as well as all the important physical effects like exchange, channel coupling, and short-range correlations have been considered in the present calculations. The present relativistic calculations for this ion using the lowest 20 target levels of Si III in the LSJ coupling scheme will enhance the database sufficiently for practical applications of photoionization cross sections of Si II.

Photoionization of ground 1s2 2s2 2p6 1Se0 and excited 1s2 2S22p53S 3Po0,1,2 states of Si V using relativistic Breit–Pauli R-matrix method

2006 ◽  
Vol 84 (8) ◽  
pp. 707-715 ◽  
Author(s):  
AK S Jha ◽  
N Singh ◽  
N Verma ◽  
M Mohan
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Configuration Interaction ◽  
Matrix Method ◽  
Relativistic Effects ◽  
Wave Functions ◽  
Close Coupling ◽  
R Matrix ◽  
Matrix Expansion ◽  
Target States

The close-coupling R-matrix method has been used to calculate photoionization cross sections for the ground and the lowest three excited states using the relativistic Breit–Pauli approximation. Configuration interaction wave-functions are used to represent eleven lowest LSJ target states of Si VI retained in the R-matrix expansion. Relativistic effects are clearly revealed from resonance converging on the excited states of Si VI.PACS No.: 32.80.Fb

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.

AB INITIO R-MATRIX/MULTI-CHANNEL QUANTUM DEFECT THEORY APPROACH TO STUDY MOLECULAR CORE EXCITATION AND IONIZATION: GSCF4R

2005 ◽  
Vol 04 (01) ◽  
pp. 35-47 ◽  
Author(s):  
MIYABI HIYAMA ◽  
NOBUHIRO KOSUGI
Keyword(s):  
Ab Initio ◽  
Quantum Defect ◽  
Theory Approach ◽  
Core Excitation ◽  
Close Coupling ◽  
R Matrix ◽  
Continuum States ◽  
Molecular Core ◽  
Quantum Defect Theory ◽  
Correlation Term

The ab initio program package named GSCF4R, which is based on the polyatomic R-matrix/MQDT (multi-channel quantum defect theory), has been developed using Gaussian type basis functions for the bound and continuum states to analyze the near edge feature of molecular inner shell excitations. The GSCF4R code is constructed by improvement and extension of the ordinal static exchange (STEX) approach. The R-matrix approach used in GSCF4R is beyond multi-channel multi-reference extensions of STEX, since it is based on the close coupling method augmented with the correlation term solved in the inner part of the R-matrix sphere. Simplification of the input data in GSCF4R has demonstrated that the R-matrix/MQDT method could be widely used in analysis of the molecular inner shell excitation and ionization. The quantum defects of the Rydberg states converging to the lowest valence ionized state NO +(1∑+) and the lowest N1 s ionized state N ⋆ O +(3Π) have been calculated.

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