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Journal ArticleDOI

RMATRX1: Belfast atomic R-matrix codes

TL;DR: RMATRX1 as mentioned in this paper is a general program to calculate atomic continuum processes using the R -matrix method, including electronatom and electron-ion scattering, and radiative processes such as bound-bound transitions, photoionization and polarizabilities.
About: This article is published in Computer Physics Communications.The article was published on 1995-12-01. It has received 679 citations till now. The article focuses on the topics: Matrix method & Radiative transfer.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a complete software package for the computation of various atomic data such as energy levels; radiative transition; collisional excitation; ionization by electron impact, photoionizatio...
Abstract: We describe a complete software package for the computation of various atomic data such as energy levels; radiative transition; collisional excitation; ionization by electron impact, photoionizatio...

1,055 citations

Journal ArticleDOI
TL;DR: H ULLAC as mentioned in this paper, an integrated code for calculating atomic structure and cross sections for collisional and radiative atomic processes, is based on relativistic quantum mechanical calculations including configuration interaction.
Abstract: We describe H ULLAC , an integrated code for calculating atomic structure and cross sections for collisional and radiative atomic processes. This code evolved and has been used over the years, but so far, there was no coherent, comprehensive, and in-depth presentation of it. It is based on relativistic quantum mechanical calculations including configuration interaction. The collisional cross sections are calculated in the distorted wave approximation. The theory and code are presented, emphasizing the various novel methods that has been developed to obtain accurate results very efficiently. In particular we describe the parametric potential method used for both bound and free orbitals, the factorization–interpolation method applied in the derivation of collisional rates, the phase amplitude approach for calculating the continuum orbitals and the N JGRAF graphical method used in the calculation of the angular momentum part of the matrix elements. Special effort has been made to insure the simplicity of use, which is demonstrated in an example.

437 citations

Journal ArticleDOI
TL;DR: The R-matrix method has been used in many applications in physics, such as elastic scattering, inelastic and radiative capture reactions, and in nuclear physics as discussed by the authors.
Abstract: The different facets of the R-matrix method are presented pedagogically in a general framework. Two variants have been developed over the years: (i) The 'calculable' R-matrix method is a calculational tool to derive scattering properties from the Schrodinger equation in a large variety of physical problems. It was developed rather independently in atomic and nuclear physics with too little mutual influence. (ii) The 'phenomenological' R-matrix method is a technique to parametrize various types of cross sections. It was mainly (or uniquely) used in nuclear physics. Both directions are explained by starting from the simple problem of scattering by a potential. They are illustrated by simple examples in nuclear and atomic physics. In addition to elastic scattering, the R-matrix formalism is applied to inelastic and radiative-capture reactions. We also present more recent and more ambitious applications of the theory in nuclear physics.

286 citations

Journal ArticleDOI
TL;DR: The XSTAR atomic database that contains a large quantity of atomic rates for use in spectral modeling of astrophysical plasmas is reported on, including incorporation of photoionization cross sections from the Opacity Project for all levels of every ion, and state-specific recombination rates.
Abstract: We report on the XSTAR atomic database that contains a large quantity of atomic rates for use in spectral modeling of astrophysical plasmas. The database includes atomic energy levels, line wavelengths, radiative transition probabilities, electron impact excitation rates, photoionization cross section, recombination rate coefficients, electron impact ionization rates, and fluorescence and Auger yields. The species considered are all the ions of H, He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, and Ni. The database collects recent data from many sources including CHIANTI, TOPbase, ADAS, NIST, and the IRON Project. Two particular features of the database are the incorporation of photoionization cross sections from the Opacity Project for all levels of every ion, and state-specific recombination rates. State-specific collisional ionization and three-body recombination are also included. The collection of data is used to build excitation-ionization models of each ion for calculation of their spectra for electron densities of up to 1018 cm-3 and temperatures between 100 and 109 K. In addition, every ion model is designed to converge to LTE under appropriate conditions. These models and data are implemented in the photoionization modeling code XSTAR v.2.

241 citations


Cites methods from "RMATRX1: Belfast atomic R-matrix co..."

  • ..., HFR [55]) and in the R-matrix scattering method [56,57], the latter including radiative and Auger damping through an optical model potential [58]....

    [...]

  • ...Structure data were computed with the multiconfiguration codes HFR (Pauli Hamiltonian) [55], AUTOSTRUCTURE (Breit–Pauli Hamiltonian) [66,67], and GRASP92 (Dirac–Coulomb–Breit Hamiltonian) [68], and the photoionization cross-sections with the Breit–Pauli R-matrix suite of codes [56,57] and AUTOSTRUCTURE....

    [...]

Journal ArticleDOI
Oleg Zatsarinny1
TL;DR: BSR is a general program to calculate atomic continuum processes using the B-spline R-matrix method, including electron–atom and electron–ion collision processes, and radiative processes such as bound–bound transitions, photoionization and polarizabilities.

240 citations

References
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01 Jan 1935
TL;DR: In this paper, the quantum mechanical method is applied to the theory of complex spectra and the Russell-Saunders case is used to obtain the energy levels of one-electron spectra.
Abstract: 1. Introduction 2. The quantum mechanical method 3. Angular momentum 4. The theory of radiation 5. One-electron spectra 6. The central-field approximation 7. The Russell-Saunders case: energy levels 8. The Russell-Saunders case: eigenfunctions 9. The Russell-Saunders case: line strengths 10. Coupling 11. Intermediate coupling 12. Transformations in the theory of complex spectra 13. Configurations containing almost closed shells. X-rays 14. Central fields 15. Configuration interaction 16. The Zeeman effect 17. The Stark effect 18. The nucleus in atomic spectra Appendix. Universal constants and natural atomic units.

2,607 citations

Book
01 Jan 1935
TL;DR: In this paper, the quantum mechanical method is applied to the theory of complex spectra and the Russell-Saunders case is used to obtain the energy levels of one-electron spectra.
Abstract: 1. Introduction 2. The quantum mechanical method 3. Angular momentum 4. The theory of radiation 5. One-electron spectra 6. The central-field approximation 7. The Russell-Saunders case: energy levels 8. The Russell-Saunders case: eigenfunctions 9. The Russell-Saunders case: line strengths 10. Coupling 11. Intermediate coupling 12. Transformations in the theory of complex spectra 13. Configurations containing almost closed shells. X-rays 14. Central fields 15. Configuration interaction 16. The Zeeman effect 17. The Stark effect 18. The nucleus in atomic spectra Appendix. Universal constants and natural atomic units.

2,552 citations

Journal ArticleDOI
TL;DR: The Oxford MCP/MCDF and MCBP/BENA packages have been rewritten in FORTRAN 77 and combined in the new code, GRASP, which is more versatile than its predecessors, contains more stable and accurate numerical procedures and a simplified but more flexible interface.

1,188 citations

Book
01 Jan 1960

1,185 citations

Journal ArticleDOI
TL;DR: Quantum defect theory (QDT) as mentioned in this paper is a unified theory of bound states, including series perturbations, autoionisation and electron-ion scattering, both elastic and inelastic.
Abstract: Quantum defect theory (QDT) is concerned with the properties of an electron in the field of a positive ion and, in particular, with expressing those properties in terms of analytical functions of the energy. It provides a unified theory of bound states, including series perturbations, autoionisation and electron-ion scattering, both elastic and inelastic. The main emphasis of the review is on the foundations of the theory. Properties of Coulomb functions are discussed in some detail and outline sketches are given of relevant topics in collision theory and radiative theory. One-channel and many-channel QDT are discussed separately. Applications to the following problems are considered: resonances, atomic collision calculations, systems with two energy levels of the ion core, helium, other rare gases, alkaline earths and other atomic systems, molecular hydrogen, dielectronic recombination.

919 citations