Dr. Hari Varma

Dr. Hari Varma
Phone : 01905-267064
EMail : hari[at]iitmandi[dot]ac[dot]in
Address : School of Basic Sciences
IIT Mandi, Kamand Campus,
Mandi - 175075
India

Research interests

  • Electronic structure and dynamics of atomic systems: Atoms and Clusters
  • Photoionization dynamics of atoms trapped in fullerene cage
  • Electron scattering studies of atomic systems
  • Above threshold ionization studies (ATI) of atoms under ultra-intense x-ray radiation

Education

  • PH.D. from I.I.T. Madras, Chennai(2008)
  • M.Sc. from I.I.T. Madras, chennai(2002)
  • B.Sc. from M.G. University, kerala(2000)

Work experience

  • Associate Professor, IIT Mandi (2017-present)
  • Assistant Professor, IIT Mandi (2010-2017)
  • Post-doctoral fellow, National Taiwan University, Taipei (2009-2010)
  • Post-doctoral fellow, Argnonne National Laboratory, U.S.A (2008-2009)

Books/Book Chapters

  • Photoabsorption processes in some free and confined atomic systems: Effects of Correlation, Relativistic Interactions and Confinement,
    Hari R Varma and P. C. Deshmukh,
    Lambert Academic Publishing,Germany, 2011.

  • Autoionization resonances in mercury atom,
    Sindhu Kalyadan, Hari R. Varma and P.C. Deshmkh,
    Electron Collision Processes in Atomic and Molecular Physics,
    Edited by P.C.Minaxi Vinodkumar, Narosa Publications, ISBN 978-81-8487-343-6, 104-108 (2014).

  • Ashish Kumar, Sindhu Kalyadan, H. R. Varma and P. C. Deshmukh,
    Quadrupole effects in the low energy photoionization of the 3s subshell of Mg@C60,
    Electron Collision Processes in Atomic and Molecular Physics,
    Edited by P.C.Minaxi Vinodkumar, Narosa Publications, ISBN 978-81-8487-343-6, Page no.-168-171(2014).

Publications in peer reviewed journals

  • Simultaneous real and momentum space electron diffraction from a fullerene molecule,
    R Aiswarya, R Shaik, J Jose, HR Varma, HS Chakraborty,
    Physical Review Letters 133 (3), 033002(2024).

  • EWS Time Delay in Low Energy e−C60 Elastic Scattering,
    R Aiswarya, R Shaik, J Jose, HR Varma, HS Chakraborty,
    Atoms 12 (3), 18(2024).

  • Quadrupole Effects in the Photoionisation of Sodium 3s in the Vicinity of the Dipole Cooper Minimum,
    Nishita M.Hosea, Jobin Jose, Hari R. Varma, Pranawa C. Deshmukh and Steven T. Manson,
    Atoms 2023, 11(10), 125(2023).

  • Density functional treatment of photoionization of sodium clusters: effects of cluster-size and exchange-correlation framework
    Rasheed Shaik, Hari R. Varma and Himadri S. Chakraborty
    Atoms 11 (8), 114(2023).

  • Plasmonic Resonant Intercluster Coulombic Decay,
    Rasheed Shaik, Hari R. Varma, Mohamed El-Amine Madjet, Fulu Zheng, Thomas Frauenheim, and Himadri S. Chakraborty,
    Phys. Rev. Lett. 130, 233201(2023).

  • Modifications in the angular photoemission time delay in Ar@C^{q=−1}_{60}: Coulomb confinement resonance as an amplifier of the spin-orbit-interaction-activated interchannel coupling effect,
    Afsal Thuppilakkadan, Sourav Banerjee, and Hari R. Varma,
    Phys. Rev. A 107, 052804(2023).

  • Near-threshold Cooper minimum in the photoionisation of the 2p subshell of sodium atom and its impact on the angular distribution parameter
    Nishita hosea, Jobin Jose and Hari R. Varma,
    J. Phys. B: At. Mol. Opt. Phys. 55, 135001(2022).

  • Confinement enhanced spin-orbit interchannel coupling effect on the atomic photoionization,
    Afsal Thuppilakkadan, Jobin Jose, and Hari R. Varma,
    J. Phys. B: At. Mol. Opt. Phys. 54 145001(2021).

  • Photoionization dynamics of Ar trapped in a fullerene anion: Coulomb confinement resonances in 2s subshell and its impact on the 3s,
    Afsal Thuppilakkadan, Jobin Jose, and Hari R. Varma,
    Phys. Scr. 96, 104004 (2021).

  • Collective effects in photoionization of sodium clusters: plasmon resonance spill, induced attractive force and correlation minimum,
    Rasheed Shaik, Hari R Varma, Himadri S Chakraborty,
    Journal of Physics B: Atomic, Molecular and Optical Physics 54, 125101(2021).

  • Electronic structure and dynamics of confined atoms,
    P C Deshmukh, J Jose, H R Varma, S T Manson,
    The European Physical Journal D 75 (6), 1-32 (2021).

  • Systematic study of Coulomb confinement resonances of atoms trapped inside charged fullerenes,
    Afsal Thuppilakkadan, Jobin Jose, and Hari R. Varma,
    Physical Review A 102 (6), 062826 (2020).

  • Photoionization phase shift and Wigner time delay of endohedrally confined atoms using transient phase methods,
    Subhasish Saha, Afsal Thuppilakkadan, Hari R Varma, Jobin Jose,
    Eur. Phys. J. Plus 135, 753 (2020).

  • Photoionization dynamics of endohedrally confined atomic H and Ar: a contrasting study between compact versus diffused model potential,
    Subhasish Saha, Afsal Thuppilakkadan, Hari R Varma, Jobin Jose,
    Journal of Physics B: Atomic, Molecular and Optical Physics 52 (14), 145001 (2019).

  • Wigner–Eisenbud–Smith photoionization time delay due to autoioinization resonances,
    PC Deshmukh, A Kumar, HR Varma, S Banerjee, Steven T Manson, VK Dolmatov, AS Kheifets,
    Journal of Physics B: Atomic, Molecular and Optical Physics 51 (6), 065008(2018).

  • Wigner photoemission time delay from endohedral anions,
    Ashish Kumar, Hari R Varma, Pranawa C Deshmukh, Steven T Manson, Valeriy K Dolmatov, Anatoli Kheifets,
    Phys. Rev. A 94, 043401(2016).

  • Photoabsorption studies of some closed-shell ions in the La isonuclear sequence,
    Sindhu Kalyadan, Hari R Varma, PC Deshmukh, JT Costello, P Hayden, ST Manson,
    Phys. Rev. A 91, 053422 (2015).

  • Relativistic effects in photoionization time delay near the Cooper minimum of noble gas atoms,
    Soumyajit Saha, Ankur Mandal, Jobin Jose, Hari R. Varma, P. C. Deshmukh, A. S. Kheifets, V. K. Dolmatov and S. T. Manson,
    Phys. Rev. A. 90, 053406 (2014) (Selected by the editors of Physical Review A to be an Editors' suggestion).

  • Photoionization of Ca 4s in a spherical attractive well potential: Dipole, quadrupole and relativistic effects,
    A. Kumar, H. R. Varma, P. C. Deshmukh and S. T. Manson,
    J.Phys. B: At. Mol. & Opt. Phys. 47 185003 (2014).

  • Pronounced effects of interchannel coupling in high-energy photoionization,
    W. Drube,T. Grehk, S. Thiess, G. B. Pradhan, H. R. Varma, P. C. Deshmukh and S. Manson,
    J.Phys. B: At. Mol. & Opt. Phys. 46, 245006 (2013).

  • Photoionization of atomic krypton confined in the fullerene C60,
    J. George, H. R. Varma, P. C. Deshmukh and S. T. Manson,
    J. Phys. B: At. Mol. Opt. Phys., 45, 185001 (2012).

  • Core Correlation Effects in the Valence Photodetachment of Cu-,
    J. Jose, H. R. Varma, P. C. Deshmukh, S. T. Manson, and V. Radojevic'
    Proc. 26th Summer School and International Symposium on the Physics of Ionized Gases (SPIG 2012),
    Book of Contributed Papers & Abstracts of Invited Lectures and Progres Reports(Contributed Paper), pp. 39-42.

  • Controlling x-rays with light: ultrafast transparency,
    T. E. Glover, M. P. Hertlein, S. H. Southworth, T. K. Allison, J. van Tilborg, E. P. Kanter, B. Krässig, H. R. Varma, B. Rude, R. Santra, A. Belkacem, and L. Young,
    Nature Physics 6, 69(2010).

  • Above-threshold ionization in the x-ray regime,
    Hari R. Varma, Marcelo F. Ciappina, Nina Rohringer, Robin Santra,
    Phys. Rev. A 80, 053424(2009).

  • X-ray-absorption near-edge structure of laser dressed neon,
    Hari R. Varma, Lin Pan, Donald R. Beck, Robin Santra,
    Phys. Rev. A 78, 065401(2008).

  • Theoretical and experimental demonstration of the existence of quadrupole Cooper minima,
    P. C. Deshmukh, T. Banerjee , H. R. Varma, O. Hemmers, R. Guilllemin, D. Rolles, A. Wolska, S. W. Yu, D. W. Lindle, W. R. Johnson and S. T. Manson,
    J. Phys. B: At. Mol. & Opt. Phys. (Fast Track) 41, 021002(2008).

  • Confinement, correlation and relativistic effects on the photoionization of 6s subshell of Hg,
    H. R. Varma, Tanima Banerjee, S. Sunilkumar, P.C. Deshmukh, S. T. Manson and V. Dolmatov.
    Journal of Physics: Conference Series (JPCS) 80, 012025(2007).

  • Selective interchannel coupling as computational strategy to interpret complex atomic spectrum,
    H. R. Varma, T. Banerjee and P. C. Deshmukh, Special Issue of Indian Journal of Physics 81, 1069(2007).

  • Correlation and relativistic effects on the photoionization of confined atoms,
    H. R. Varma, P. C. Deshmukh, V. K. Dolmatov and S. T. Manson,
    Phys. Rev. A 76, 012711(2007).

    •
  • Resonance-induced deviations of beta from 2.0 for rare gas s-subshell photoionization,
    S. B. Whitteld, R. Wehlitz, H. R. Varma, T. Banerjee, P. C. Deshmukh and S. T. Manson,
    , J. Phys. B 39, L335(2006).

  • Interchannel coupling effects on non-dipole photoionization parameters,
    P. C. Deshmukh, Tanima Banerjee, K. P. Sunanda and Hari Varma R.,
    Radiation Physics and Chemistry 12, 2211(2006).

  • Absolute photoionization cross sections and resonance structure of doubly ionized silicon in the region of the 2p-1 threshold: Experiment and theory,
    J. -P. Mosnier, M. H. Sayyad, E. T. Kennedy, J.-M. Bizau, D. Cubaynes, F. J. Wuilleumier, J. -P. Champeaux, C. Blancard, R. Hari Varma, T. Banerjee, P. C. Deshmukh and S. T. Manson,
    Phys. Rev. A 68, 052712(2003).

Publications in conference proceedings

Presentations in conferences (Posters/Talks)

  • Photoabsorption studies of some closed-shell ions in the La isonuclear sequence,
    Sindhu Kalyadan, Hari R. Varma, P. C. Deshmukh, John Costello and P. Hayden
    The 11th Asian International conference on Atomic and Molecular Physics, Sendai, Japan, 6-10 October 2014.
  • Photoionization studies of Cd@C60,
    Ashish Kumar, Sindhu Kalyadan, Hari R. Varma, Pranawa C. Deshmukh, Steven T. Manson
    The 44th Annual Meeting of the Division of Atomic, Molecular and Optical Physics (DAMOP 2013) of the American Physical Society, Cuebec city, Canada, 3-7 June 2013.
  • Sindhu Kannur, Gagan B. Pradhan, Jobin Jose, Hari R. Varma, P. C. Deshmukh and S. T. Manson. Dramatic quadrupole effects in the low energy photoionization of the 4s subshell of free and confined Ca , In The 42nd Annual Meeting of the Division of Atomic, Molecular and Optical Physics (DAMOP 2012) of the American Physical Society held at Anaheim, California, June 4-8 2012
  • Jobin Jose, Sindhu Kannur, Ashish Kumar, Hari R. Varma, P. C. Deshmukh and S. T. Manson. Time delay in photoionization near Cooper minimum, In The 42nd Annual Meeting of the Division of Atomic, Molecular and Optical Physics (DAMOP 2012) of the American Physical Society held at Anaheim, California, 2012.
  • Ashish Kumar, Sindhu Kannur, Hari R. Varma, and P. C. Deshmukh. Time Delay Study on Xe@C60; DAE-BRNS Symposium on Atomic, Molecular and Optical Physics IISER Kolkata, 14-17 December 2012.
  • Sindhu Kalyadan, Ashish Kumar, H. R. Varma, John Costello and P. C. Deshmukh. Autoionization Resonances in the 6.Xnm Spectral Range; DAE-BRNS Symposium on Atomic, Molecular and Optical Physics IISER Kolkata, 14-17 December 2012.
  • J. George , Hari R. Varma , P. C. Deshmukh , S. T. Manson. Effect of Interchannel Coupling and Confinement on the Photoionization of Kr. In XXVII International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2011) Belfast, Northern Ireland, UK,27 July - 2 August, 2011
  • T Banerjee , Hari R Varma , P C Deshmukh , S T Manson. Dipole and Quadrupole Photoionization of Intermediate Subshells of Atomic Mercury. In XXVII International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2011) Belfast, Northern Ireland, UK,27 July - 2 August, 2011.
  • Cooper minima in E2 photoionization of xenon, Gagan Bihari Pradhan, Jobin Jose, Hari R. Varma, T. Banerjee and P. C. Deshmukh, T. C. on Atomic and Molecular Physics, Sardar Patel Universtiy India, January 3-5(2008).
  • Some recent studies in the photoionization of free and confined atoms, INVITED TALK at the XV Ith NCAMP, TIFR, Mumbai, India, january 8-11(2007).
  • Autoionization resonances in @Kr and @Xe, Hari R. Varma and P. C. Deshmukh, XVI NCAMP, TIFR, Mumbai, Jan 8-11(2007).
  • E1 & E2 photoionization studies of free and confined cadmium and mercury, Hari R. Varma, S. Sunil Kumar, Tanima Banerjee and P. C. Deshmukh, XVI NCAMP, TIFR, Mumbai, Jan 8-11(2007).
  • Confinement effects on E1 and E2 photoionization of the ns subshells of atomic krypton and xenon T. Banerjee, Hari R. Varma and P. C. Deshmukh, XVI NCAMP, TIFR, Mumbai, Jan 8-11(2007).
  • Spin-polarization of Photoelectrons from Atomic Krypton, Anand Joshi, Saheer Ahmed, H. R. Varma, T. Banerjee,,S. Majumder, Y. Khajuria, P.C. Deshmukh, NSSA 2006, Calcutta, Jan 18-20 (2006).
  • Autoionization resonances in atomic Cd using multi channel quantum defect theory, Hari R. Varma, Tanima Banerjee, Saheer Ahmed, Anand Joshi, Y. Khajuria, S. Majumder and P. C. Deshmukh, T. C. on Atomic, Molecular and Optical Physics, IACS, Kolkatta, India, December 21-23(2005).
  • Interference between dipole excitation and ionization channels in confined atoms, Hari R.Varma, Y. Khajuria, S. Majumder and P. C. Deshmukh, T. C. on Atomic and Molecular Physics, IACS, Calcutta, Dec 21-23(2005).
  • Consequences of quantum confinement on atomic photoionization parameters, Hari R. Varma and P. C. Deshmukh, XV NCAMP, Physical Research Laboratory, Ahmedabad, India, December 20-23(2004).
  • Interchannel coupling effects on non-dipole photoionization paramters of atomic xenon and mer- cury, Tanima Banerjee, K. P. Sunanda, Hari Varma R, Ummal Momeen, P. C. Deshmukh, XV NCAMP, Physical Research Laboratory, Ahmedabad, India, December, 20-23(2004).
  • Newly found dynamical effects on photoelectron parameters in the dipole approximation for atomic Xe, K. P. Sunanda, Tanima Banerjee, Hari Varma R, Ummal Momeen, P.C.Deshmukh, XV NCAMP, Physical Research Laboratory, Ahmedabad, India, December, 20-23 (2004).

Research Projects

  • Photoabsorption Studies on Atomic Systems
    Sponsoring agency: IIT Mandi (seed-grant)
    Grant total: Rs. 3, 20, 000

  • Collision Processes in Atomic and Molecular Physics
    Sponsoring agency: DST India
    Grant total Rs. 25, 67, 520
    Co-investigator: Dr. P. C. Deshmukh (IIT Madras)

    • Co-investigator of the following project:
  • Towards a Laser Plasma Light Source Platform for Next Generation Extreme-UV Lithography (EUVL): Theoretical and Experimental Spectrsocopic Studies at 6.X nm
    Sponsoring agency: DST (international)
    Grant total: Rs. 3,54,000.00
    Principal Investigators: Dr. P. C. Deshmukh (IIT Madras, chennai)& Dr. John costello (DCU, Dublin)
    Other co-investigators: Dr. Lampros Nikolopoulos, Dr. Patrick Hayden, Prof. Eugene Kennedy (DCU, Dublin)

Group Members

    Graduate students
  • Ms. Sindhu Kalyadan
  • Mr. Ashish Kumar

    • Project Students
  • Ms. Afsal Thuppilikkadan
  • Mr. Thejus Mahajan

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