Professor: Department of Astronomy, Chemical Physics Program, Interdisciplinary Biophysics Graduate Program

The Ohio State University, Columbus, Ohio, USA 43210

Director and Co-Founder: Indo-US Center for STEM Education and Research

Email:, Phone: 614-292-5850


Atomic, Molecular, Optical, & Plasma Physics
Astronomy and Astrophysics
Biophysics and Nanotechnology
High-Performance Computing

NEWS: Press and Media Reports

TEXTBOOK: Bridging Physics and Astronomy
Atomic Astrophysics and Spectroscopy (AAS) Anil K. Pradhan and Sultana N. Nahar (Cambridge University Press)

Leadership for Academicians Programme (LEAP)
U.S.-India STEM Faculty Training Project
The Opacity Project and The Iron Project
X-ray Nano-Biophysics: Resonant Nano-Plasma Theranostics
Women in STEM Roadshows in India

OPSERVER - Opacities (Ohio Supercomputer Center)
OSU-NORAD (Nahar Database)
Electron Impact Excitation
Electron-Ion Recombination

Astronomy 2140 - Planets and the Solar System (Introductory Undergraduate)
Astronomy 2141 - Life in the Universe (Undergraduate)
Astronomy 1141 - Life in the Universe (Introductory Undergraduate)
Astronomy 1143 - History of the Universe: Cosmology (Introductory Undergraduate)
Astronomy 1144 - Stars, Galaxies and Universe (Introductory Undergraduate)
Astronomy 1140 - Planets and the Solar System (Introductory Undergraduate)
Astronomy 162 - Stars and Galaxies (Introductory Undergraduate)
Astronomy 641 - Stellar Astrophysics (Advanced Undergraduate)
Astronomy 823 - Theoretical Spectroscopy (Graduate)
Scattering Theory (Graduate), Univ. of Colorado
Atomic Physics (Graduate), Univ. of Windsor
Atomic and Molecular Radiation Physics: Astronomy to Biomedicine Special Graduate Course: University of Delhi, Aligarh Muslim University
Opacity: Theoretical and Astrophysical Aspects Atomic Radiation Physics Minicourse, The 41st IEEE Intenational Conference on Plasma Science 2014

Astronomy vs. Astrology: Uptodate Zodiac Signs and Dates
Auger Effect in Biomedicine
Physics of Global Warming - Solar Irradiance (Sultana Nahar, Ref: Recent Publications)
Astronomy Day: Studying Our Star, the Sun Sultana Nahar and Anil Pradhan


This homepage reports interdisciplinary research by the OSU group, jontly with Sultana Nahar and several students, postdocs, and collaborators. Research interests are theoretical studies of radiative and collisional atomic processes, and spectral formation and opacities in astrophysical and laboratory plasmas - an integrated program of atomic physics, astrophysics, and plasma physics.


Plasma effects on resonant phenomena", Anil Pradhan, to appear in Can. J. Phys. (2024).

Interface of Equation-of-State, Atomic Data and Opacities in the Solar Problem" Anil K. Pradhan, MNRAS Letters, 527, L179 (2024).

R-Matrix calculations for opacities: RMOP-I. Methodology and computations, A.K. Pradhan, S.N. Nahar and W. Eissner (to appear in J. Phys.B)

R-Matrix calculations for opacities.RMOP-II. Photoionization and oscillator strengths of iron ions FeXVII, FeXVIII and FeXIX, S.N. Nahar, L. Zhao, W. Eissner and A.K. Pradhan (to appear in J. Phys.B)

R-matrix calculations for opacities: RMOP-III. Plasma broadening of autoionizing resonances, A.K. Pradhan (to appear in J. Phys.B)

R-Matrix calculations for opacities: RMOP-IV. Convergence, completeness, and comparison of relativistic R-matrix and distorted wave calculations for FeXVII and FeXVIII, L. Zhao, S.N. Nahar and A.K. Pradhan (to appear in J. Phys.B)

Photoionization and Opacity , Anil Pradhan, Atoms 11, 52 (2023)

Werner Eissner (1930-2022): A pioneer in Computational Atomic Physics, Anand K. Bhatia, Anthony E. Lynas-Gray, Claudio Mendoza, Sultana Nahar, Harry Nussbaumer, Anil K. Pradhan, Anthony M. Seaton, Gunter Wunner and Claude J. Zeippen, Atoms 1, 0 (2023)

Plasma broadening of autoionizing resonances, Anil Pradhan,

Recalculation of astrophysical opacities: overview, methodology and atomic calculations , Anil Pradhan and Sultana Nahar, Proceedings of Workshop on Astrophysical Opacities, ASP Conf. Ser. 515, 79 (2018)

Converged Close-Coupling R-Matrix calculations of Photoionization of Fe XVII in Astrophysical Plasmas: from Convergence to Completeness , Lianshui Zhao, Werner Eissner, Sultana Nahar and Anil Pradhan, Proceedings of Workshop on Astrophysical Opacities, ASP Conf. Ser. 515, 89 (2018)

The IRON Project: Photoionization of Fe Ions, Sultana N. Nahar, Proceedings of Workshop on Astrophysical Opacities, ASP Conf. Ser. 515, 93 (2018)

Comment by A.K. Pradhan on "Fe XVII opacity at stellar interior conditions" by C.A. Iglesias and S. Hansen (2017).

Large enhancement in high-energy photoionization of FeXVII and missing continuum plasma opacity S.N. Nahar and A.K. Pradhan, Phys. Rev. Letts., 116, 235003 (2016).

Reply to Comment by Blancard et al. (2016) , Sultana N. Nahar and Anil K. Pradhan, Phys. Rev. Letts. 117, 249502 (2016).

A higher-than-predicted measurement of iron opacity at solar interior temperatures" , J.E. Bailey et al. (22 authors including Sultana N. Nahar, Anil K. Pradhan and C. Orban from OSU), Nature 517, 56 (2015).

Highly Excited Core Resonances in Photoionization of Fe XVII : Implications for Plasma Opacities , Sultana N. Nahar, Guoxin Chen, Werner Eissner, Anil K. Pradhan, Phys. Rev. A 83, 032417 (2011).

Opacities for stellar envelopes , M.J. Seaton, Y. Yu, D. Mihalas and Anil K. Pradhan, Mon. Not. Roy. Astr. Soc. 266, 805 (1994).

Extra-solar Spectral Biosignatures

Biosignature Line Ratios of [P II] in Exoplanetary and Nebular Environments, Kevin Hoy, Sultana Nahar & Anil Pradhan, MNRAS, 521, L48 (2023).

Collision strengths for FIR and UV transitions in PIII and the phosphorus abundance , Rahla Naghma, Sultana N Nahar and Anil K Pradhan, Mon. Not. Roy. Soc. Letters, 479, L60 (2018).

Monte Carlo Simulations of Biophysical Factors for Viability of Life in Exoplanetary Atmospheres" , Maximililian Westphal and Anil Pradhan, Workshop on Astrophysical Opacities , Aug. 1-4, 2017, Western Michigan University, Kalamazoo, MI.

STEM Education and Research

``World Class STEM Faculty: An International Dual-Degree Program", Karen E. Irving, Anil K. Pradhan and Sultana N. Nahar, Book Chapter in "Recruiting, Preparing, and Retaining stem Teachers for a Global Generation", 217-240, 2019, Publ: Brill Sense (Leiden, Boston), Eds: J. Leonard, A.C. Burrows and R. Kitchen, ISBN: 978-90-04-39998-3 (paperback), 978-90-04-39997-6 (hardback), 978-90-04-39999-0 (e-book).

X-ray Nanobiophysics

Interdisciplinary program in biophysics: Computational Nanoscience and Biomedical X-ray Spectroscopy. Researchers include Max Westphal (Biophysics Graduate Program), Sultana Nahar (Astronomy), Chris Orban (Physics), Russell Pitzer (Chemistry), Enam Chowdhury (Physics), Sara Lim (Medical College of Wisconsin))

Recent developments entail theoretical and experimental studies to implement a new methodology, RESONANT NANO-PLASMA THERANOSTICS , based on the use of monochromatic X-ray sources for imaging, therapy and diagnostics (theranostics) in cancer research, as reported in the following news items.

*** News Media Reports on Group Research ***


2. X-ray researchers turn focus from black holes to cancer: International team leverages resources of Ohio Supercomputer Center

3. Tailored X-rays for cancer, news story published in Nature-India, 29 November 2009.


The Opacity Project and the Iron/RmaX Project

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: Proceedings of the Symposium at the Institute of Theoretical Atomic and Molecular Astrophysics (ITAMP) at the Harvard-Smithsonian Center for Astrophysics in honor of M. J. Seaton (Iron Project meeting organized by Anil Pradhan and Sultana Nahar)