ANIL K. PRADHAN Professor, Department of Astronomy, Adjunct Professor, Chemical Physics, The Ohio State University E-mail: pradhan@astronomy.ohio-state.edu OR pradhan.1@osu.edu, Ph: 614-292-5850, Fax: 614-292-2928

MAIN RESEARCH AREAS PHOTOIONIZATION RECOMBINATION COLLISION STRENGTHS TRANSITION PROBABILITIES ASTROPHYSICAL SPECTROSCOPY OPACITIES

DATABASE (Updates: Nahar) ENERGY LEVELS ELECTRON IMPACT EXCITATION ELECTRON-ION RECOMBINATION TRANSITION PROBABILITIES PHOTOIONIZATION CROSS SECTIONS

COURSES TAUGHT Astronomy 161 - Solar System Astronomy 162 - Stars and Galaxies Astronomy 823 - Astrophysical Spectroscopy (Graduate) Astronomy 641 - Stellar Astrophysics Scattering Theory (Graduate), Univ. of Colorado Atomic Physics (Graduate), Univ. of Windsor

ATOMIC ASTROPHYSICS AND SPECTROSCOPY

Greetings! This homepage reports the research by the OSU Atomic Astrophysics Group, with senior Research Scientist Sultana Nahar, Postdoctoral Fellow Chiranjib Sur, Graduate student Maximiliano Montenegro and collaborators.

Research interests are theoretical studies of radiative and collisional atomic processes, and spectral formation in astrophysical plasmas - an integrated program of atomic physics and astronomy.

New directions in theoretical atomic physics research include a combination of Relativistic Coupled Cluster Method (RCCM) and the R-matrix method.

This website will also report on the activties of a new INTERDISCIPLINARY COMPUTATIONAL NANOSCIENCE initiative devoted to nanospectroscopy of material and biological nanostrcutures. The group comprises of Russell Pitzer (Chemistry), Sultana Nahar (Astronomy), Yan Yu (Thomas Jefferson University Medical School), postdoctoral fellow Chiranjib Sur, and graduate students Mike Mrozik, and Maximiliano Montenegro. The program was supported by a Large Interdisciplinary Grant Award from the OSU Office of Research, College of Mathematical and Physical Sciences, and the Department of Astronomy.

The OSU group represents the U.S. participants in the international Opacity Project (OP) , and the Iron Project (IP/RmaX) Network aimed at large-scale atomic calculations using the relativistic R-matrix method for iron-peak elements and X-ray astrophysics. The databases TIPTOPBASE and OPSERVER offer OP and IP atomic data, and on-line calculation of "customized" astrophysical opacities, at the Ohio Supercomputer Center in Columbus Ohio.

This homepage is also intended as a guide to recommended ATOMIC DATA for astrophysical and laboratory applications. In addition, the database Nahar OSU Radiative Data (NORAD) contains a large number of datafiles for energy levels, transition probabilities, photoionization cross sections, and total and partial (electron+ion) recombination rate coefficients (including radiative and dielectronic recombination processes in a unified and ab initio manner using the R-matrix method).

The radiative data supercede earlier TOPbase data.

---

HIGH ACCURACY ATOMIC PHYSICS IN ASTRONOMY

PUBLICATIONS: 1995 -

Recent Publications: 2007 -

1. ``A comprehensive Set of UV and X-ray Radiative Transition Rates for Fe XVI", S. N. Nahar, W. Eissner, C. Sur, A. K. Pradhan, Physica Scripta (submitted).
2. "On the importance of satellite lines to the He-like K$\alpha$ complex and the G ratio for calcium, iron, and nickel, Justin Oelgoetz, Christopher J. Fontes, Hon Lin Zhand, Sultana N. Nahar, Anil K. Pradhan, Mon. Not. R. Astro. Soc. (submitted)
3. "Electron-Ion Recombination Rate Coefficients and Photoionization Cross Sections for Astrophysically Abundant Elements. XV. Rate Coefficients For Dielectronic Satelline Lines of Fe~XXV and Ni~XXVII", Sultana N. Nahar, Justin Oelgoetz, and Anil K. Pradhan, (submitted).
4. "Electron-Ion Recombination Rate Coefficients and Photoionization Cross Sections for Astrophysically Abundant Elements. XIV. C-like Fe~XXI including high-energy resonances", Sultana N. Nahar, J. Quant. Spec. Rad. Transf. (in press).
5. "K-alpha transition probabilities for F-like ions from Neon to Gold: Ab initio relativistic coupled-cluster calculations", Chiranjib Sur, Sultana N. Nahar and Anil K. Pradhan, Phys. Rev. A, 77, 1 (2008).
6. "Oscillator strengths and radiative transition rates for K$_{\alpha}$ lines in gold X-ray spectra: 1s-2p transitions", Sultana N. Nahar, Anil K. Pradhan, and Chiranjib Sur, J. Quant. Spec. Rad. Transf., 109, 1951 (2008).
7. "XMM-Newton observations of the Narrow-Line Seyfert 1 galaxy Mkn 335 in an historical low X-ray flux state", Dirk Grupe, Stefanie Komossa, Luigi C. Gallo, Andrew C. Fabian, Josefin Larsson, Anil K. Pradhan, Dawei Xu, Giovanni Miniutti, Astrophys. J., 681, 982 (2008).
8. "A relativistic unitary coupled-cluster study of electric quadrupole moment and magnetic dipole hyperfine constants of ^199 Hg^+", Chiranjib Sur and R. K. Chaudhuri, Phys. Rev. A. , *76*, 032503 (2007).
9. "Relativistic multi-reference Fock-space coupled-cluster calculation of the forbidden ^1 S_0 -- ^3 D_1 magnetic-dipole transition in ytterbium", Chiranjib Sur and R. K. Chaudhuri, Phys. Rev. A. , *76*, 012509 (2007).
10. "Breakdown of the quasistatic approximation at high densities and its effect on the heliumlike K$\alpha$ complex of nickel, iron, and calcium", Justin Oelgoetz, Christopher J. Fontes, Hong Lin Zhang, and Anil K. Pradhan, Phys. Rev. A 76, 062504 (2007)
11. "PHOTOIONIZATION, RECOMBINATION, AND RADIATIVE DECAYS OF ATOMS AND IONS", Sultana N. Nahar, Proceedings of the Conference on "New Quests in Stellar Astrophysics. II. Ultraviolet Properties of Evolved Stellar Populations", Puerto Vallarta, Mexico on April 16 - 20, 2007 (in press)
12. "Next Generation UV Coronagraph Instrumentation for Solar Cycle-24", John L. Kohl, Rajmal Jain, Steven R. Cranmer, Larry D. Gardner, Anil K. Pradhan, John C. Raymond, and Leonard Strachan, Proceedings of the conference on Challenges For Solar Cycle-24, Physical Research Laboratory, India, Jan 22-27, 2007
13. "High-temperature behaviour of the helium-like K-alpha G ratio: the effect of improved recombination rate coefficients for calcium, iron, and nickel", J. Oelgoetz, C. J. Fontes, H.L. Zhang, M. Montenegro, S.N. Nahar, and A. K. Pradhan, Mon. Not. R. Astr. Soc. 382, 761 (2007).
14. Branching ratios of radiative transitions in OVI, Chiranjib Sur and Rajat K. Chaudhuri (J.Phys.B, 40, 4307, 2007.
15. "OPserver: interactive on-line computations of opacities and radiative accelerations", C. Mendoza, M.J. Seaton, P. Buerger, A. Bellorin, M. Melendez, J. Gonzalez, L.S. Rodriguez, F. Delahaye, E. Palacios, A.K. Pradhan and C.J. Zeippen, Mon. Not. R. Astron. Soc. 378, 1031 (2007).
16. "Effects of partial triple excitations in atomic coupled cluster calculations", Chiranjib Sur and Rajat K. Chaudhri, Chem. Phys. Lett., 442, 150-156 (2007).

    
    REVIEW: Self-Consistent R-matrix Approach To Photoionization And Unified Electron-Ion Recombination , Sultana N. Nahar and Anil K. Pradhan, Radiation Physics and Chemistry 70 (2004) 323-344, Elsevier (astro-ph/0310624)

    Revised: August 1, 2008