2002/07/10 by Sultana N. Nahar, Nahar, Sultana N.
Earth and Planetary Sciences · Physics and Astronomy · #Advanced Chemical Physics Studies #Astrophysics (astro-ph) #Atmospheric Ozone and Climate #Atomic Physics (physics.atom-ph) #Atomic and Molecular Physics #FOS: Physical sciences #astro-ph #physics.atom-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0207224
4 pgs., 4 color figs., in Proceedings of the Workshop on Stellar Atmosphere Modeling, Tuebingen, Germany, April 8-12, 2002. High-res figures from http://www.astronomy.ohio-state.edu/~pradhan
arxiv created 2002/07/10 · openalex publication_date 2002/07/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Most astrophysical plasmas entail a balance between ionization and\nrecombination. We present new results from the powerful R-matrix method which\nyields in an ab initio manner: (I) self-consistent photoionization and\nrecombination cross sections using identical wavefunction expansions, (II)\nunified e-ion recombination rates at all temperatures of interest,\nincorporating non-resonant and resonant processes, radiative and dielectronic\nrecombination (RR and DR), and (III) level-specific recombination rates for\nmany excited atomic levels. RR and DR processes can not be measured or observed\nindependently. In contrast to the shortcomings of simple (but computationally\neasy) approximations that unphysically treat RR and DR separately with\ndifferent methods, emphasizing marginal effects for selected ions over small\nenergy ranges, the R-matrix method naturally and compeletely accounts for e-ion\nrecombination for all atomic systems.\n Photoionization and recombination cross sections are compared with\nstate-of-the-art experiments on synchrotron radiation sources and ion storage\nrings. Overall agreement between theory and experiments is within 10-20 %. For\nphotoionization the comparison includes not only the ground state but also the\nmetastable states, with highly resolved resonance structures. The recent\nexperiments therefore support the estimated accuracy of the vast amount of\nphotoionization data computed under the Opacity Project (OP), the Iron Project\n(IP), and related works using the R-matrix method.\n