Related papers: The Iron Project and Non-LTE stellar modeling
A hot central star illuminating the surrounding ionized H II region usually produces very rich atomic spectra resulting from basic atomic processes: photoionization, electron-ion recombination, bound-bound radiative transitions, and…
Recent advances in theoretical atomic physics have enabled large-scale calculation of atomic parameters for a variety of atomic processes with high degree of precision. The development and application of these methods is the aim of the Iron…
Most astrophysical plasmas entail a balance between ionization and recombination. We present new results from the powerful R-matrix method which yields in an ab initio manner: (I) self-consistent photoionization and recombination cross…
A unified scheme using the R-matrix method has been developed for electron-ion recombination subsuming heretofore separate treatments of radiative and dielectronic recombination (RR and DR). The ab initio coupled channel approach unifies…
Theoretically self-consistent calculations for photoionization and (e + ion) recombination are described. An identical eigenfunction expansion for the ion is employed in coupled channel calculations for both processes, thus ensuring…
The IRON Project, initiated in 1991, aims at two main objectives, i) study the characteristics of and calculate large-scale high accuracy data for atomic radiative and collisional processes, and ii) application in solving astrophysical…
The Opacity Project (OP) and Iron Project (IP) are pioneering international collaborations which have been computing, for more than 25 years, massive atomic data sets for astrophysical applications. We review the data activities that have…
Opacity determines radiation transport through material media. In a plasma source the primary contributors to atomic opacity are bound-bound line transitions and bound-free photoionization into the continuum. We review the theoretical…
Relativistic atomic structure calculations for electric dipole E1, electric quadrupole E2 and magnetic dipole M1 transition probabilities among the first 80 fine-structure levels of Fe VI, dominated by configurations 3d^3, 3d^24s, and…
Ar XIII is found to be unique with new features in electron-ion recombination not seen in any other ion. The ion has been studied with the unified method which provides a theoretically self-consistent set of atomic parameters for the…
An extended version of the R-matrix methodology is presented for calculation of radiative parameters for improved plasma opacities. Contrast and comparisons with existing methods primarily relying on the Distorted Wave (DW) approximation…
Recently, Bailey et al. (2015) made a direct measurement of the Iron opacity at the physical conditions of the solar tachocline. They found that the wavelength-integrated Iron opacity is roughly 75% higher that what the OP and OPAL models…
Several years ago, M. Asplund and coauthors (2004) proposed a revision of the Solar composition. The use of this new prescription for Solar abundances in standard stellar models generated a strong disagreement between the predictions and…
Dielectronic recombination (DR) is the dominant recombination process for most heavy elements in photoionized clouds. Accurate DR rates for a species can be predicted when the positions of autoionizing states are known. Unfortunately such…
Here we report new ${\it ab initio}$ calculations of the effective recombination coefficients for the \ion{N}{ii} recombination spectrum. We have taken into account the density dependence of the coefficients arising from the relative…
We present multi-configuration Breit-Pauli AUTOSTRUCTURE calculations of distorted-wave photoionization (PI) cross sections, and total and partial final-state resolved radiative recombination (RR) and dielectronic recombination (DR) rate…
The first complete set of unified cross sections and rate coefficients are calculated for photoionization and recombination of He- and Li-like ions using the relativistic Breit-Pauli R-matrix method. We present total, unified (e + ion)…
Iron-group elements have a very high number of atomic levels and an overwhelming number of spectral lines. No NLTE model-atmosphere code can cope with these in a classical way. A statistical approach was developed over the last decade to…
Photoionization and its inverse, electron-ion recombination, are key processes that influence many astrophysical plasmas (and gasses), and the diagnostics that we use to analyse the plasmas. In this review we provide a brief overview of the…
Convergence of the Rosseland Mean Opacity (RMO) is investigated with respect to the equation-of-state (EOS) and the number of atomic levels of iron ions prevalent at the solar radiative/convection boundary. The "chemical picture"…