Photoionization, Recombination, and Radiative Transitions of Atoms and Ions

  • Sultana N. Nahar
Conference paper
Part of the Astrophysics and Space Science Proceedings book series (ASSSP)


Physical properties such as temperature, density of stars and their chemical compositions can be obtained from detail analysis of their spectra at various wavelengths. Ultraviolet (UV) wavelengths are particularly important as the chromosphere surrounding a star is rich in UV radiation generated by collisional and radiative atomic processes, such as photoionization, electron-ion recombination and bound-bound radiative transitions in the plasma. For both precise diagnostics and astrophysical modelings, accurate atomic parameters for these processes are essential. I report the latest developments in theoretical quantum mechanical calculations, especially under the two international collaborations known as the Opacity Project (OP, The Opacity Project Team 1995, 1996) and the Iron Project (IP, series in A&A 1993-), that have yielded accurate and large-scale atomic data for photoionization cross sections, oscillator strengths, and collision strengths for electron impact excitation of the most astrophysically abundant atoms and ions, and the extension, total and level-specific electron-ion recombination cross sections and rates. The calculations are carried out in anab initio manner using the accurate and powerful R-matrix method, including relativistic fine structure effects for many ions, in the close-coupling approximation.


Radiative Recombination Photoionization Cross Section Dielectronic Recombination Radiative Decay Rate Radiative Recombination Rate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Arnaud, M., & Raymond, J. 1992, ApJ, 398, 394CrossRefADSGoogle Scholar
  2. Atomic data from the Iron Project series. 1993-Astron. Astrophys.; data files available at CDS.Google Scholar
  3. Bell, R. H., & Seaton, M. J. 1985, J. Phys. B 18, 1589CrossRefADSGoogle Scholar
  4. Hummer D. G., Berrington K. A., Eissner W., et al. 1993, A&A, 279, 298 (IP)ADSGoogle Scholar
  5. Mendoza, C., Seaton. M. J., et al. 2007, MNRAS 378, 1031CrossRefADSGoogle Scholar
  6. Nahar, S. N. 1997, Phys. Rev. A 55, 1980CrossRefADSGoogle Scholar
  7. Nahar, S. N. 2004, ApJS, 156, 93CrossRefADSGoogle Scholar
  8. Nahar, S. N. 2007a (He cross sections are from R-matrix, unpublished)Google Scholar
  9. Nahar, S. N. 2007b (to be submitted)Google Scholar
  10. Nahar S. N., Eissner, W., Chen, G.X., & Pradhan, A.K. 2003, A&A, 408, 789CrossRefADSGoogle Scholar
  11. Nahar S. N., Eissner, W., Pradhan, A.K., & Sur, C. 2007, in preparationGoogle Scholar
  12. Nahar, S. N., & Pradhan, A.K. 1992, Phys. Rev. Lett. 68, 1488CrossRefADSGoogle Scholar
  13. Nahar, S.N., & Pradhan, A.K. 1993, J. Phys. B 26, 1109CrossRefADSGoogle Scholar
  14. Nahar, S.N., & Pradhan, A.K. 1994, Phys. Rev. A 49, 1816CrossRefADSGoogle Scholar
  15. Nahar, S.N., & Pradhan, A.K. 2000, Phys. Scr. 61, 675CrossRefADSGoogle Scholar
  16. Nahar, S. N., Pradhan, A.K. & Zhang, H.L. 2001, ApJS 133, 255CrossRefADSGoogle Scholar
  17. Seaton, M. J., 1987, J. Phys. B, 20, 6363CrossRefADSGoogle Scholar
  18. The Opacity Project vols 1 & 2, compiled by the Opacity Project Team: Institute of Physics, London UK 1995 and 1996 — (OP)Google Scholar
  19. Verner, D. A., & Ferland G. 1996, ApJS, 103, 467CrossRefADSGoogle Scholar
  20. Woods, D. T., Shull, J. M., & Sarazin, C. L. 1981, ApJ, 249, 399CrossRefADSGoogle Scholar
  21. Yu, Y., & Seaton, M. J. 1987, J. Phys. B, 20, 6409CrossRefADSGoogle Scholar
  22. Zhang, H. L., Nahar, S. N., & Pradhan, A. K. 1999, J. Phys. B, 32. 1459CrossRefADSGoogle Scholar
  23. Zhang, H. L., Nahar, S. N., & Pradhan, A. K. 2001, Phys. Rev. A, 64, 032719CrossRefADSGoogle Scholar

Copyright information

© Springer-Verlag New York 2009

Authors and Affiliations

  1. 1.Department of AstronomyThe Ohio State UniversityColumbusUSA

Personalised recommendations