Research

Understanding the mechanisms and dynamics of chemical reactions addresses the most fundamental question of why and how chemical reactions happen. We are interested in the computational studies of the processes that happen during a chemical reaction. The computer simulations provide an atomistic and microscopic level of understanding of chemical reactions. Different approaches, namely, classical, quantum, semi-classical, and statistical theories have been used to study the various systems depending on the nature of the system and the properties of interest. Although accurate dynamics is described by quantum mechanics, it is extremely difficult to apply it for systems with many atoms. For many chemical systems classical mechanics gives an accurate description of the dynamics. We use classical trajectories simulations as a tool to study the dynamics of chemical reactions. The simulation results are compared with experiments.

43. Influence of second-order saddles on reaction mechanisms
K. Yadav, R. Pradhan, and U. Lourderaj Faraday Discuss. (Accepted) (2022)

42. HeH⁺ Collisions with H₂: Rotationally Inelastic Cross Sections and Rate Coefficients from Quantum Dynamics at Interstellar Temperatures
K. Giri, L. González-Sánchez, R. Biswas, E. Yurtsever, F. Gianturco, N. Sathyamurthy, U. Lourderaj, and R. Wester J. Phys. Chem. A (Accepted) (2022)

41. Synthesis and computational aspects of Al(II)-Al(II) and Ga(II)-Ga(II) dihalides based on an amidinate scaffold
A. Kumar, S. Banerjee, N. Sharma, M. Nazish, N. Graw, R. Herbst-Irmer, D. Stalke, U. Lourderaj, and H. W. Roesky Dalton Trans. 51, 4898 (2022)

40. Palladium-catalyzed selective C–C bond cleavage and stereoselective alkenylation between cyclopropanol and 1, 3-diyne: one-step synthesis of diverse conjugated enynes
B. V. Pati, A. Ghosh, K. Yadav, S. K. Banjare, S. Pandey, U. Lourderaj, and P. C. Ravikumar Chem. Sci. 13, 2692 (2022)

39. Stereomutation in Tetracoordinate Centers via Stabilization of Planar Tetracoordinated Systems
K. Yadav, U. Lourderaj, and U. Deva Priyakumar Atoms 9, 79 (2021) Special Issue: Planar Tetracoordinate Carbon - Fifty Years and Beyond

38. Second-order Saddle Dynamics in Isomerization Reaction
R. Rashmi, K. Yadav, U. Lourderaj, and M. Paranjothy Regul. Chaotic Dyn. 26, 26 (2021) Special Issue (Eds. G. Ezra and S. Wiggins)

37. Mechanism and Dynamics of CH₂NO₂^- + CCl₄ Halophilic Reaction
S. Mitra, S. S. Dutta, N. Sharma, and U. Lourderaj Int. J. Mass Spectrom. 459, 116470 (2021)

36. Dynamics of a gas phase S_NAr reaction: Non-concerted mechanism despite the Meisenheimer complex being a transition state
N. Sharma, R. Biswas, and U. Lourderaj Phys. Chem. Chem. Phys. 22, 26562 (2020)

35. Transition between [R]- and [S]-Stereoisomers without Bond Breaking
S. Ragunathan, K. Yadav, V. C. Rojisha, T. Jaganade, V. Prathyusha, S. Bikkina, U. Lourderaj and U. D. Priyakumar Phys. Chem. Chem. Phys. 22, 14983 (2020)

34. Machine Learning in Chemical Dynamics
R. Biswas, R. Rashmi and U. Lourderaj Resonance 25, 59-75 (2020)

33. Computational Studies on the Excited-State Intramolecular Proton Transfer in Five-Membered-Ring Hydrogen-Bonded Systems
R. Pradhan and U. Lourderaj in Hydrogen-Bonding Research in Photochemistry, Photobiology, and Optoelectronic Materials Edited by Keli Han and Guangjiu Zhao, Chapter 7, 155-178 (2019)

32. Theoretical Investigation of the Isomerization Pathways of Diazenes: Torsion vs. Inversion
A. Sindhu, R. Pradhan, U. Lourderaj and M. Paranjothy Phys. Chem. Chem. Phys. 21, 15678 (2019)

31. Can Reactions Follow Non-traditional Second-order Saddle Pathways avoiding Transition States?
R. Pradhan and U. Lourderaj, Phys. Chem. Chem. Phys. 21, 12837 (2019) - 2019 PCCP HOT Articles

30. Quantum chemical investigation of the thermal denitrogenation of 1-pyrazoline
R. Pradhan and U. Lourderaj, Phys. Chem. Chem. Phys. 19, 27468 (2017)

29. Isolation and Characterization of Regioisomers of Pyrazole-Based Palladacycles and Their Use in α-Alkylation of Ketones Using Alcohols
R. Mamidala, S. Samser, N. Sharma, U. Lourderaj, and K. Venkatasubbaiah, Organometallics 36, 3343 (2017)

28. Classical Dynamics Simulations of Dissociation of Protonated Tryptophan in the Gas Phase
Y. Krishnan, N. Sharma, U. Lourderaj, and M. Paranjothy, J. Phys. Chem. A 121, 4389 (2017)

27. Time-Dependent Density Functional Theoretical Investigation of Photoinduced Excited-State Intramolecular Dual Proton Transfer in Diformyl Dipyrromethanes
R. Pradhan, A. K. Harshan, G. S. K. Chandrika, A. Srinivasan, and U. Lourderaj, J. Phys. Chem. A 120, 9894 (2016)

26. Mechanisms and Dynamics of Protonation and Lithiation of Ferrocene
N. Sharma , J. K. Ajay, K. Venkatasubbaiah, and U. Lourderaj, Phys. Chem. Chem. Phys. 17, 22204 (2015)

25. Photoenolization via Excited State Double Proton Transfer Induces "turn on" Fluorescence in Diformyl Diaryl Dipyrromethane
K. C. G. Sreedevi, A. P. Thomas, K. H. Aparna, R. Pradhan, M. L. P. Reddy, U. Lourderaj, and A. Srinivasan, Chem. Comm. 50, 8667 (2014)

24. The VENUS/NWChem Software Package. Tight Coupling between Chemical Dynamics Simulations and Electronic Structure Theory
U. Lourderaj, R. Sun, S. C. Kohale, G. L. Barnes, W. A. de Jong, T. L. Windus, and W. L. Hase, Comp. Phys. Comm. 185, 1074 (2014)

23. Modeling the Formaldehyde-Graphene Interaction Using a Formaldehyde-Pyrene System
L. S. Dodda and U. Lourderaj, Phys. Chem. Chem. Phys. 15, 17479 (2013)

22. Simulation Studies of the Cl^- + CH₃I S_N2 Nucleophilic Substitution Reaction: Comparison with Ion Imaging Experiments
J. Zhang, U.Lourderaj, R. Sun, J. Mikosch, R. Wester, and W. L. Hase, J. Chem. Phys. 138, 14308 (2013)

21. Chemical Dynamics Simulations of CO₂ in the Ground and First Excited Bend States Colliding with a Perfluorinated Self-Assembled Monolayer
J. J. Nogueira, S. A. Vazquez, U.Lourderaj, W. L. Hase, and E. Martinez-Nunez, J. Phys. Chem. C. 114, 184455 (2010)

20. Higher-accuracy Schemes for Approximating the Hessian from Electronic Structure Calculations in Chemical Dynamics Simulations
H. Wu, M. Rahman, J. Wang, U. Lourderaj, W. L. Hase, and Y. Zhuang, J. Chem. Phys. 133, 074101 (2010)

19. Cyclohexane Isomerization. Unimolecular Dynamics of the Twist Boat Intermediate
K. Kakhiani, U. Lourderaj, W. Hu, D. Birney, and W. L. Hase, J. Phys. Chem. A 113, 4570 (2009)

18. A Ubiquitous Tool for Education in Chemical Dynamics Simulations
Y. Zhuang, W. L. Hase, P. Khadka, U. Lourderaj, and S. Baidya, Ubiquitous Learning: An International Journal1, 57 (2009)

17. Theoretical and Computational Studies of Non-RRKM Unimolecular Dynamics
U. Lourderaj and W. L. Hase, J. Phys. Chem. A 113, 2236 (2009).Centennial Feature Article

16. Quantum Chemical Calculations of the Cl + CH₃I Potential Energy Surface
J. X. Zhang, U. Lourderaj, S. V. Addepalli, W. A. deJong, and W. L. Hase, J. Phys. Chem. A 113, 1976 (2009)

15. Potential Energy Surface and Unimolecular Dynamics of Stretched n-Butane
U. Lourderaj, J. L. McAfee, and W. L. Hase, J. Chem. Phys. 129, 094701 (2008)
This paper was selected for the September 15, 2008 issue of the Virtual Journal of Biological Physics Research. The Virtual Journal is an edited compilation of links to articles from participating publishers, covering a focused area of frontier research.

14. A Grid-Based Cyber Infrastructure for High Performance Chemical Dynamics Simulations
K. Prashant, Y. Zhuang, U. Lourderaj, and W. L. Hase, Journal of Systemics, Cybernetics and Informatics 6, 10 (2008)

13. Classical Trajectory Simulations of Post-Transition State Dynamics
U. Lourderaj, K. Park, and W. L. Hase, Int. Rev. Phys. Chem. 27, 361 (2008)

12. Chemical Dynamics Simulations of Energy Transfer in Collisions of Protonated Peptide-Ions with Perfluorinated Alkylthiol Self-Assembled Monolayer Surfaces
L. Yang, O. A. Mazyar, U. Lourderaj, J. Wang, M. T. Rodgers, E. Martinez-Nunez, S. V. Addepalli, and W. L. Hase, J. Phys. Chem. C 112, 9377 (2008)

11. Imaging Nucleophilic Substitution Dynamics
J. Mikosch, S. Trippel, C. Eichhorn, R. Otto, U. Lourderaj, J. X. Zhang, W. L. Hase, M. Weidemuller, and R. Wester, Science 319, 183 (2008)
This paper was selected for "Year in Review" issue in Chemical and Engineering News that was published on December 22, 2008. This issue highlights the most significant research in chemical sciences during the year 2008.

10. Representing and Selecting Vibrational Angular Momentum States for Quasiclassical Trajectory Chemical Dynamics Simulations
U. Lourderaj, E. Martinez-Nunez, and W. L. Hase, J. Phys. Chem. A 111, 10292 (2007)

9. A Direct Dynamics Trajectory Study of F^. + CH₃OOHReactive Collisions Reveals a Major Non-IRC Reaction Path
J. G. Lopez, G. Vayner, U. Lourderaj, S. V. Addepalli, S. Kato, W. A. deJong, T. L. Windus, and W. L. Hase, J. Am. Chem. Soc. 129, 9976 (2007)

8. Direct dynamics simulations using Hessian-based predictor-corrector integration algorithms
U. Lourderaj, K. Song, T. L. Windus, Y. Zhuang, and W. L. Hase, J. Chem. Phys. 126, 044105 (2007)

7. Ab initio quantum chemical investigation of the ground and excited states of salicylic acid dimer
S. Maheshwary, U. Lourderaj, and N. Sathyamurthy, J. Phys. Chem. A 110, 12662 (2006)

6. Ground and excited states of the monomer and dimer of certain carboxylic acids
U. Lourderaj, K. Giri, and and N. Sathyamurthy, J. Phys. Chem. A 110, 2709 (2006)

5. Determination of stability and degradation in polysilanes by an electronic mechanism
A. Sharma, U. Lourderaj, Deepak, and N. Sathyamurthy, J. Phys. Chem. B 110, 15860 (2005)

4. Ab initio potential energy surface of HeF₂ in its ground electronic state
U. Lourderaj and N. Sathyamurthy, Chem. Phys. 308, 277 (2005)

3. Stability in polysilanes for light emitting diodes
A. Sharma, U. Lourderaj, Deepak, N. Sathyamurthy and M. Katiyar, Comp. Mat. Sci. 33, 206 (2005)

2. Conformational Control and Photoenolization of Pyridine-3-carboxaldehydes in the Solid State: Stabilization of Photoenols via Hydrogen Bonding and Electronic Control
P. Mal, U. Lourderaj, Parveen, P. Venugopalan, J. N. Moorthy, and N. Sathyamurthy, J. Org. Chem. 68, 3446 (2003)

1. Time-dependent density functional theoretical study of low lying excited states of F₂
U. Lourderaj, Manoj K. Harbola and N. Sathyamurthy, Chem. Phys. Lett. 88, 366 (2002)

Conference Proceedings (Refereed)

1. A Grid-Based Cyber Infrastructure for High Performance Chemical Dynamics Simulations
K. Prashant, Y. Zhuang, U. Lourderaj, and W. L. Hase, Proc. 4th International Conference on Cybernetics and Information Technologies, Systems and Applications, July 2007

2. Kinematically complete chemical reaction dynamics
S. Trippel, M. Stei, R. Otto, P. Hlavenka, J. Mikosch, C. Eichhorn,U. Lourderaj, J. X. Zhang, W. L. Hase, M. Weidemuller, and R. Wester, Journal of Physics: Conference Series 194, 012046 (2009)

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