<i>R</i>-matrix Calculation of C III Bound and Continuum Fine-structure States

Berrington, K A; Pelan, John; Quigley, Lisa

doi:10.1088/0031-8949/57/5/002

Cited by 13 publications

(15 citation statements)

References 21 publications

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“…) agrees quite well with the measured value [29] as well as with other calculations [36,37,39,41,42].…”

Section: Energies and Oscillator Strengths Of C Iiisupporting

confidence: 91%

“…) agrees within the uncertainty of the measured value by Kwong et al [34] and with the result from Berrington et al [39], while that from Froese Fisher et al [36,37] agrees almost exactly with the measured value by Doerfert et al [35]. Froese Fischer et al [36,37] included the Breit interaction in an indirect manner and found the effect to be important for the intercombination transitions.…”

Section: Energies and Oscillator Strengths Of C Iiisupporting

confidence: 86%

“…Berrington et al [39] calculated the BPRM oscillator strengths for transitions among the levels of the two symmetries, J = 0 e and J = 1 o of configurations 1s 2 2snl and 1s 2 2pnl for n going up to 10. They employed an eigenfunction expansion with 28 fine-structure core levels and correlation orbitals going up to l ≤ 4.…”

Section: Energies and Oscillator Strengths Of C Iiimentioning

confidence: 99%

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Fine Structure Radiative Transitions in C Ii and C Iii Using the Breit–pauli R-Matrix Method

Nahar

2002

Atomic Data and Nuclear Data Tables

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Extensive sets of radiative transitions in C II and in C III are obtained using the relativistic Breit-Pauli R-matrix (BPRM) method. In comparison with other accurate methods that can be applied to relatively few transitions, the BPRM method enables calculations of a large number of transitions with comparable accuracy for most of them. The present work reports large-scale calculations for two important ions obtaining 127 and 206 bound fine structure energy levels, resulting in 1681 and 4202 dipole allowed and intercombination transitions for C II and C III, respectively. Detailed comparison of the BPRM results is made with those from experimental and theoretical studies, including the relativistic multiconfiguration Dirac-Fock method. INTRODUCTIONThe Breit-Pauli R-matrix (BPRM) method [1] is being used to calculate a large number of oscillator strengths (f -values) [2][3][4][5]. The first large scale application of the BPRM method for the radiative transitions in Fe XXIV and Fe XXV [2] showed very good agreement, within 10%, of the f -values with the most accurate theoretical calculations available. Most of the experimental and theoretical studies for oscillator strengths and transition probabilities (A-values) are focused on a few or a limited number of transitions, whereas various spectral diagnostic models and astrophysical applications, such as plasma opacities, require f -or A-values for a very large number of transitions. Systematic calculations for radiative processes were carried out for most astrophysically abundant atoms and ions under the Opacity Project (OP [6][7][8][9]). The datasets obtained under the OP are available electronically through a database, TOPbase [10]. The calculations under the OP were carried out in LS coupling and no relativistic effects were considered. However, fine structure transitions, rather than LS multiplets, are needed for spectral diagnostics in astrophysical and laboratory plasmas. The Breit-Pauli R-matrix method developed under the Iron Project (IP, [1]) includes relativistic effects in the Breit-Pauli approximation [1,11,12] for collisional processes. Recently, the method has been extended to enable close coupling calculations of oscillator strengths (i) including the relativistic effects and (ii) considering a large number of transitions.The present study investigates the relativistic and electron-electron correlation effects in transitions of two important light ions, C II and C III. These two ions are of particular interest in the diagnostics of a number of astrophysical objects such as in early type stars and nebulae as well as in laboratory plasmas. THEORYProvided here is a brief summary of the the basics of the Breit-Pauli R-matrix method. The method for radiative bound-bound and bound-free transitions is derived from atomic collision theory and the coupled channel or close coupling (CC) approximation [1,6]. The computational method is based on the powerful R-matrix formalism that enables efficient, accurate, and large-scale calculations of compound (bound and c...

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“…) agrees quite well with the measured value [29] as well as with other calculations [36,37,39,41,42].…”

Section: Energies and Oscillator Strengths Of C Iiisupporting

confidence: 91%

Section: Energies and Oscillator Strengths Of C Iiisupporting

confidence: 86%

Section: Energies and Oscillator Strengths Of C Iiimentioning

confidence: 99%

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Fine Structure Radiative Transitions in C Ii and C Iii Using the Breit–pauli R-Matrix Method

Nahar

2002

Atomic Data and Nuclear Data Tables

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“…Recently, several relativistic calculations of transition probabilities have been carried out using the Breit-Pauli R-matrix method (BPRM); e.g. for Fe XXV and Fe XXIV (Nahar & Pradhan 1999), C III (Berrington et al 1998), Fe XXIII (Ramírez et al 2000). These calculations produced highly accurate oscillator strengths for most transitions considered, within a few percent of experimental data or other accurate theoretical calculations (where available).…”

Section: Introductionmentioning

confidence: 99%

Atomic data from the Iron Project

Nahar

Delahaye

Pradhan

et al. 2000

Astron. Astrophys. Suppl. Ser.

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An extensive set of dipole-allowed, intercombination, and forbidden transition probabilities for Fe V is presented. The Breit-Pauli R-matrix (BPRM) method is used to calculate 1.46 10 6 oscillator strengths for the allowed and intercombination E1 transitions among 3865 fine-structure levels dominated by configuration complexes with n ≤ 10 and l ≤ 9. These data are complemented by an atomic structure configuration interaction (CI) calculation using the SUPERSTRUCTURE program for 362 relativistic quadrupole (E2) and magnetic dipole (M1) transitions among 65 low-lying levels dominated by the 3d 4 and 3d 3 4s configurations. Procedures have been developed for the identification of the large number of fine-structure levels and transitions obtained through the BPRM calculations. The target ion Fe VI is represented by an eigenfunction expansion of 19 fine-structure levels of 3d 3 and a set of correlation configurations. Fe V bound levels are obtained with angular and spin symmetries SLπ and Jπ of the (e + Fe VI) system such that 2S + 1 = 5, 3, 1, L ≤ 10, J ≤ 8 of even and odd parities. The completeness of the calculated dataset is verified in terms of all possible bound levels belonging to relevant LS terms and transitions in correspondence with the LS terms. The fine-structure averaged relativistic values are compared with previous Opacity Project LS coupling data and other works. The 362 forbidden transition probabilities considerably extend the available data for the E2 and M1 transtions, and are in good agreement with those computed by Garstang for the 3d 4 transitions.

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“…Comparison between calculated width, G a , in meV units (meV), belonging to 1s 2 2pns( 1 P 0 ) autoionizing states, 5 n 12, in C 3þ . Results refer to the R-matrix Floquet theory and code and its extension to LIDS method, and the R-matrix calculation by Berrington et al (1998) In atomic or molecular physics, it is customary the use of sum rules to handle the matrix elements that appear in many computations (Biedenharn & Rose, 1953;Biedenharn, 1955). These formulae are particularly well suited for the study of autoionization of large-angular momentum doubly excited Rydberg states.…”

Section: First-order Perturbative Calculation In a Single-configuratimentioning

confidence: 99%

Theoretical calculation of atomic data for plasma spectroscopy

Stǎncǎlie

2009

Laser Part. Beams

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In the present article, a number of theoretical approximations and numerical methods, varying in complexity, are reviewed, in order to facilitate their selection for plasma diagnostic purposes. Results refer to highly charged ions, particularly in the lithium isoelectronic sequence. This article describes progress in understanding the role of laser induced degenerate state phenomenon on resonances obtained by using lasers. This type of process, implicitly included in the R-matrix Floquet calculation, contributes to some degree, to the overall behavior of the resonance profiles. The present article gives comparative results obtained from ab initio non-perturbative treatment and perturbative calculation of autoionization widths in Be-like ions. The effective oscillator strength for complex highly ionized atoms is, also, provided. Such calculations are of interest as they represent accurate benchmark data for beam emission spectroscopy, Zeff analysis, or complex atoms modeling in fusion plasma devices.

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R-matrix Calculation of C III Bound and Continuum Fine-structure States

Cited by 13 publications

References 21 publications

Fine Structure Radiative Transitions in C Ii and C Iii Using the Breit–pauli R-Matrix Method

Fine Structure Radiative Transitions in C Ii and C Iii Using the Breit–pauli R-Matrix Method

Atomic data from the Iron Project

Theoretical calculation of atomic data for plasma spectroscopy

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