Curriculum Vitae Padma Kumar Padmanabhan 245 NHB, Department of Geology University of Illinois at Urbana Champaign 1301 W. Green Street, Urbana, IL 61801, USA. Tel. : 001 217 244 2355 Fax. : 001 217 244 4996 Email: [email protected]
Personal Information:
Date and Place of Birth : 19 April 1972; Mavelikara, Kerala. Nationality : Indian. Sex & Marital Status : Male, Married with one child.
Professional Experience:
Sept 2004 - Present : Post-Doctoral Research Associate, University of Illinois at Urbana-Champaign, Urbana, USA (Adviser: Prof. R. James Kirkpatrick). Aug 2002 - Jul 2004 : Post-Doctoral Research Associate, Ruhr-Universit¨atBochum, Bochum, Germany (Adviser: Prof. Dominik Marx).
Education:
Ph. D. Indian Institute of Science, Bangalore. 2002 Thesis title: “Computer Simulation Studies of Ionic Motion in NASICON-type Superionic Conductors”. Thesis advisers: Prof. S. Yashonath and Prof. K. J. Rao M. Sc. (Physics) Dept. of Physics, University of Pune, Poona. 1995 B. Sc. (Physics) BM College, Mavelikara affiliated to University of Kerala. 1992
Awards and Honors:
2000 Senior Research Fellowship, Department of Atomic Energy, New Delhi, India. 1997 Senior Research Fellowship (SRF), CSIR, New Delhi, India. 1995 Junior Research Fellowship(JRF/NET), CSIR, New Delhi, India. 1995 Qualified Graduates Aptitude Test for Engineers (GATE). 1992 UGC Fellowship during Masters at University of Pune. . . . CV, Padma Kumar Page 2
Professional Activities:
• Member, American Chemical Society.
• Peer Reviewer for – Journal of Physical Chemistry
– Journal of Physics D: Applied Physics
– Journal of Physics: Condensed Matter
• Presentations (Conferences/Seminars): – Talk at Dept. of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, March 2007.
– Talk at Theoretical Physics, Institute of Mathematical Science, Chennai, March 2007.
– Talk at American Chemical Society Meeting September 2006, San Francisco, USA.
– Poster at Goldschmidt Conference May 2005, Moscow, Idaho, USA.
– Talk at Institute of Computational Physics, Dept. of Mathematics and Physics, Universit¨atStuttgart, Germany, April 2004.
– Talk at Lehrstuhl F¨urTheoretische Chemie, Ruhr-Universit¨atBochum, Germany, November 2002.
– Poster at the conference on “Structure and Dynamics in Complex Chemical Sys- tems”, January 2000, Indian Institute of Science, Bangalore, India.
– Poster at 5th IUMRS International conference, October 1998, Indian Institute of Science, Bangalore, India.
• Workshops Attended: – Attended Beowulf Cluster Building Workshop, Nov. - Dec. 2006, Beckman Insti- tute, University of Illinois at Urbana-Champaign.
– Attended Summer School on Computational Materials Science, July-August 2006, University of Illinois at Urbana-Champaign.
– Attended workshop on “Computational Techniques for Condensed Matter”, January 2001, Indian Institute of Science, Bangalore, India. . . . CV, Padma Kumar Page 3
Professional Skills:
• Methodological Expertise:
– Ab initio (Car-Parrinello and Born-Oppenheimer) molecular dynamics (MD).
– Ab initio metadynamics technique.
– Classical molecular dynamics in NVE, NVT and NPT ensembles.
– Classical Monte Carlo (MC) in NVT and NPT ensembles.
– Development of Interionic Potentials/Force-Fields.
• Simulation/Visualization Software Experience:
– CPMD, Cerius2, DL POLY, Matlab, VMD, Molden, Molekel, gOpenMol . . .
• Code Development:
– Molecular dynamics (NVT and NVE ensemble) codes for ionic/molecular systems.
– Monte Carlo (NVT and NPT ensemble) codes for ionic/molecular systems.
– Development of Ewald summation routines for non-cubic simulation cell.
– Development & implementation of an algorithm to remove ‘over all’ rotations for isolated system calculations on existing CPMD package.
– A number of other codes to analyze simulation trajectories.
• Programming Skills:
– Proficiency in Fortran 90 and 77.
• Teaching Experience:
– Tutor to “Programming in Fortran 90”, 1997-98, Solid State and Structural Chem- istry Unit, Indian Institute of Science, Bangalore. . . . CV, Padma Kumar Page 4
Publications:
1. “Molecular Dynamics Simulation of the Energetics and Structure of Layered Double Hydroxide Intercalated with Carboxylic Acids”, Padma Kumar, P., Andrey G. Kalinichev, and R. James Kirkpatrick; (Accepted for publication in J. Phys. Chem. C). 2. “Dissociation of Carbonic Acid: Gas Phase Energetics and Mechanism from ab ini- tio Metadynamics Simulation”, Padma Kumar, P., Andrey G. Kalinichev, and R. James Kirkpatrick; J. Chem. Phys., 126, 204315 (2007). 3. “Hydration, Swelling, Interlayer Structure, and Hydrogen Bonding in Organo-layered Double Hydroxides: Insights from Molecular Dynamics Simulation of Citrate-Intercalated Hydrotalcite”, Padma Kumar, P., Andrey G. Kalinichev, and R. James Kirkpatrick; J. Phys. Chem. B (Letter); 110, 3841-3844 (2006). 4. “Ionic Conduction in the Solid State”, Padma Kumar, P., Yashonath, S.; J. Chem. Sci., 118, 135-154 (2006).
+ 5. “Understanding Hydrogen Scrambling and Infrared Spectrum of Bare CH5 Based on ab initio Simulations”, Padma Kumar, P., Dominik Marx; Phys. Chem. Chem. Phys., 8, 573-586 (2006).
+ ∗ ∗ 6. “Understanding the Infrared Spectrum of Bare CH5 ”, Oskar Asvany , Padma Kumar, P. , Britta Redlich, Ilka Hagemann, Stephan Schlemmer, Dominik Marx; Science, 309, 1219- 1222 (2005). 7. “Quantum Corrections to Classical Time-Correlation Functions: Hydrogen Bonding and Anharmonic Floppy Modes”, Rafael Ramirez, Telesforo L´opez-Ciudad, Padma Kumar, P., Dominik Marx; J. Chem. Phys., 121, 3973-3983 (2004).
8. “Structure, Conductivity and Ionic Motion in Na1+xZr2SixP3−xO12: A Simulation Study”, Padma Kumar, P.; Yashonath, S.; J. Phys. Chem. B, 106, 7081-7089 (2002).
9. “A Full Interionic Potential for Na1+xZr2SixP3−xO12 Superionic Conductors”, Padma Kumar, P.; Yashonath, S.; J. Am. Chem. Soc. (Communication), 124, 3828-3829 (2002). 10. “Ion Mobility and Levitation Effect: Anomalous Diffusion in NASICON-type Structures”, Padma Kumar, P.; Yashonath, S.; J. Phys. Chem. B, 106, 3443-3448 (2002).
11. “Lithium Ion Motion in LiZr2(PO4)3”, Padma Kumar, P.; Yashonath, S.; J. Phys. Chem. B, 105, 6785-6791 (2001). 12. “Computer Simulation Studies of Ar Clusters”, Padma Kumar, P.; Rao, K. J.; Bull. Mater. Sci., 22, 843 (1999).
Manuscripts In Preparation:
1. “Structure, Conductivity and Phase Transitions in Na3Zr2Si2PO12: Simulation Study”, Padma Kumar, P.; Yashonath, S.; 2. “Structure of NASICON-framework upon Alkali Ion Substitution: Monte Carlo Study”, Padma Kumar, P.; Yashonath, S.;
∗These authors contributed equally to this work. . . . CV, Padma Kumar Page 5
Research Experience:
1. At University of Illinois at Urbana-Champaign
Projects: (a) Aqueous - mineral interfaces: the hydration of layered double hydrox- ides (LDHs) containing functional organic species.
(b) Hydration structure, proton transfer, and reactivity of carbonates: H2CO3, 2− − CO3 , HCO3 and CO2 in aqueous solution. Techniques: Classical and ab initio (Car-Parrinello) molecular dynamics, metadynamics. Accomplishments: • Enhanced swelling of layered double hydroxides bearing organic anions in contrast to those intercalated with inorganic species was demonstrated in molecular dynamics simulations, consistent with recent experiments. • Systematic changes in the orientation and the H-bonding patterns of the interlayer- organic-species were found associated with progressive hydration of the LDHs. • The enhanced swelling behaviour of organo-LDHs was attributed to the preference of the carboxylate species to accept hydrogen bonds from water than from the hydroxyl groups on the surface of LDH. • Our metadynamics studies provide fresh insights on the mechanism and energetics of the dissociation and conformational changes of carbonic acid in gas-phase. • A molecular level understanding of the mechanism and energetics of the inter- conversions of carbonates in aqueous environment is emerging from our ongoing ab initio molecular dynamics and metadynamics studies. 2. At Ruhr-Universit¨atBochum
Project: Large amplitude motions in small molecules: impact of pseudo rotations + on the IR spectra of protonated methane, CH5 Techniques: Ab initio (Car-Parrinello and Born-Oppenheimer) molecular dynamics. Accomplishments: • An appropriate theoretical basis for the computation of ‘classical’ infrared(IR) spec- trum was formulated through performance-evaluation of various quantum correction factors (QCFs) to the classical dipole auto correlation functions in model systems. • The existing CPMD code was adapted to remove physically uninteresting over-all rotation-translations conforming to angular- and linear- momentum conservation, as a second phase of the project. The technique is most general and is highly desired in gas-phase simulations. . . . CV, Padma Kumar Page 6
• Excellent agreement was found between the computed IR spectrum to that measured by the novel Laser Induced Reaction (LIR) technique, confirming the satisfactory level of the theoretical treatment. • Strategies for spectral assignment of such floppy molecules beyond the traditional harmonic analysis were developed. + • Spectroscopic evidence for three center two electron bonding operative in CH5 was presented. 3. At Indian Institute of Science
Project: Ion transport in framework solids: Development of interatomic potentials and Insights from computer simulation studies of NASICON-type superi- onic conductors. Techniques: Classical Monte Carlo and molecular dynamics. Accomplishments: • Developed interionic potentials to describe mobile ions in an approximated rigid framework of NASICON-type solids, by fitting to X-ray structure and DC conduc- tivity. • Fresh insights were obtained on the preferred conduction channels in the frame- work, bottlenecks and energy barriers thereof, as well as site occupancies of Li in LiZr2(PO4)3 through our MD simulations.
• The higher order phase transition observed in LiZr2(PO4)3 at 600 K was attributed to the ‘melting’ of the Li sub-lattice from an ordered phase. • Predicted an enhanced diffusion for optimally-sized ions by a phenomenon similar to the Levitation effect. Formulated a simple criterion based on the metal-oxygen distance and the geometry of the bottlenecks to observe maximum ionic conductivity in such frameworks – a very useful insight in the tailor making of superionic solids. • Successfully modeled the framework flexibility – without requiring approximations or constraints – to facilitate a comprehensive microscopic examination of a variety of NASICON-type solids, through further refinement of interaction parameters. • Structural indicators, like lattice parameters, bond lengths and angles, site occupan- cies of the mobile ions etc., as well as the ionic conductivity of Na1+xZr2SixP3−xO12 over a wide range of temperatures and compositions (0 ≤ x ≤ 3) were predicted in excellent agreement with experiments. • The role of entropic contributions to the free energy in deciding the Na+ occupancy at the various sites was demonstrated. • The microscopic origin of the monoclinic to rhombohedral phase transition in Na3Zr2Si2PO12, the best conductor of the Na1+xZr2SixP3−xO12 series, was also investigated. • Apart from resolving some of the long-standing issues, the studies discussed the role of different factors that give rise to high ionic conductivity in these materials. . . . CV, Padma Kumar Page 7
References:
1. Prof. R. James Kirkpatrick Grim Professor & Exc. Assoc. Dean of Liberal Arts and Science 203 NHB, Department of Geology University of Illinois at Urbana-Champaign 1301 W.Green St., Urbana, IL 61801, U.S.A. Phone: 001-217-333-7414 Fax: 001-217-244-4996 E-mail: [email protected] http://www.geology.uiuc.edu/∼kirkpat/index.html
2. Dr. Andrey G. Kalinichev Senior Research Scientist 111-a NHB, Department of Geology University of Illinois at Urbana-Champaign 1301 W.Green St., Urbana, IL 61801, U.S.A. Phone: 001-217-333-4389 Fax: 001-217-244-4996 E-mail: [email protected] http://www.geology.uiuc.edu/%7Ekalinich/
3. Prof. Dominik Marx Distinguished Professor of Theoretical Chemistry Lehrstuhl F¨urTheoretische Chemie Ruhr-Universit¨atBochum D-44780 Bochum, Germany. Tel : 0049 (0)234 32 28083 Fax : 0049 (0)234 32 14045 Email: [email protected] http://www.theochem.ruhr-uni-bochum.de
4. Prof. S. Yashonath Solid state and Structural Chemistry Unit Indian Institute of Science Bangalore-560 012, India. Tel : 0091 (0)80 3942796 Fax : 0091 (0)80 360 1310 Email: [email protected] http://sscu.iisc.ernet.in/faculty pages/yasho.html
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