Fine structure cross sections from reactance matrices

Saraph, H. E.

doi:10.1016/0010-4655(72)90071-9

Cited by 193 publications

(55 citation statements)

References 5 publications

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“…Mendoza & Zeippen (1987) reported electron excitation rates for transitions between the fine-structure 2s 2 2p 4 3 P 0,1,2 , 1 D 2 and 1 S 0 levels from their close-coupling calculations. The LS coupled reactance matrices were transformed to intermediate coupling by ignoring the relativistic effects and by using the JAJOM program (Saraph 1972(Saraph , 1978. Butler & Zeippen (1994) performed a six-state (2s 2 2p 4 3 P, 1 D, 1 S, 2s2p 5 3 P o , 1 P o and 2p 6 1 S) R-matrix calculation to obtain electron excitation collision strengths for O-like ions including Mg V. They also performed an algebraic transformation of LS reactance matrices to intermediate coupling.…”

Section: Introductionmentioning

confidence: 99%

Collision rates for electron excitation of Mg V lines

Tayal

Sossah

2015

A&A

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Aims. Transition probabilities and electron impact excitation collision strengths and rates for astrophysically important lines in Mg V are reported. The 86 fine-structure levels of the 2s 2 2p 4 , 2s2p 5 , 2p 6 , 2s 2 2p 3 3s, 2s 2 2p 3 3p and 2s 2 2p 3 3d configurations are included in our calculations. The effective collision strengths are presented as a function of electron temperature for solar and other astrophysical applications.Methods. The collision strengths have been calculated using the B-spline Breit-Pauli R-matrix method for all fine-structure transitions among the 86 levels. The one-body mass, Darwin and spin-orbit relativistic effects are included in the Breit-Pauli Hamiltonian in the scattering calculations. The one-body and two-body relativistic operators are included in the multiconfiguration Hartree-Fock calculations of transition probabilities. Several sets of non-orthogonal spectroscopic and correlation radial orbitals are used to obtain accurate description of Mg V 86 levels and to represent the scattering functions. Results. The calculated excitation energies are in very good agreement with experiment and represents an improvement over the previous calculations. The present collision strengths show good agreement with the previously available R-matrix and distorted-wave calculations. The oscillator strengths for E1 transitions normally compare very well with previous calculations. The thermally averaged collision strengths are obtained by integrating total resonant and non-resonant collision strengths over a Maxwellian distribution of electron energies and these are presented over the temperature range log 10 T e = 3.2−6.0 K.

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Section: Introductionmentioning

confidence: 99%

Collision rates for electron excitation of Mg V lines

Tayal

Sossah

2015

A&A

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“…More recently, Fawcett & Mason (1991) reconsidered the atomic data calculations of Flower (1977). Although based on the same computer package composed of DISTWAV (Eissner & Seaton 1972), JAJOM (Saraph 1972(Saraph , 1978 and SUPERSTRUCTURE (Eissner et al 1974), this study included an adjustment of Slater parameters (Fawcett & Mason 1989) using a subroutine in the HFR code of Cowan (1981). Also, a lack of consistency in the level indexing in the work of Flower was corrected.…”

Section: Introductionmentioning

confidence: 99%

Atomic data from the IRON Project

Storey

Zeippen

Dourneuf

2002

A&A

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Abstract. We calculate collision strengths and thermally averaged collision strengths for electron excitation between the one hundred and forty energetically lowest levels of Fe 8+ . The scattering target is more elaborate than in any earlier work and large increases are found in the excitation rates among the levels of the 3s 2 3p 5 3d electron configuration due to resonance series that have not been considered previously. The implications for solar and stellar spectroscopy have been discussed elsewhere (Storey & Zeippen 2001). We correct some errors that were made in generating the figures given in that paper and present corrected versions.

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“…In order to compare results from the nonrelativistic CCC calculations with experiment, we have used a technique essentially identical with the transformation scheme described by Saraph [33]. Namely, we first transform the non-relativistic CCC scattering amplitudes f S π f s f l f m f ,π i s i l i m i to the amplitudes describing transitions between fine-structure levels J f and J i , parity, spin, orbital angular momentum is and its projection on the Z-axis of the collision frame, respectively.…”

Section: A CCC Methodsmentioning

confidence: 99%