Coherent motions in form of specific delocalized nuclear motions usually arising from low-frequency modes have been frequently suspected to play a key role in photoactive systems. Consequently, tracing transient changes in atomic positions and elucidating reactive nuclear coordinates within a polyatomic system becomes imperative. Using combination of steady-state electronic spectroscopy along with pump-probe electronic and time-resolved Raman spectroscopy, our group aims to develop a unified mechanism of photoactive systems driven by collective motions in many of the potent artificial and natural molecular systems. In addition, we are also working towards unravelling the role of protein motions in chemically triggered enzyme action.

In the quest for renewable energy, developing an inexpensive light harvesting technology will be incumbent upon us within the next few decades as we move away from the finite natural resources. In this context, designing new materials for photocatalytic processes with high photochemical efficiencies is crucial. One of the key features in all new materials will be its robustness during the entire catalytic cycle. We are exploring ways in which we can stabilize reactive intermediates inside environments conducive to multi-electron reactions.

• R. Frontiera, C. Fang, J. Dasgupta and R.A. Mathies, Probing structural evolution along multidimensional reaction coordinates with femtosecond stimulated Raman; Phys. Chem. Chem. Phys. (2012) 14, 405-14
• K. Spillane, J. Dasgupta and R.A. Mathies, Conformational homogeneity and excited state isomerization dynamics of the bilin chromophore in Cph1 from Resonance Raman intensities, Biophys. J. (2012) 102, 709-17
• A. Jha and J. Dasgupta, Femtosecond Stimulated Raman Spectroscopy: Potential tool to monitor chemical reaction dynamics, ISRAPS bulletin (2013)
• J. Dasgupta, A.M. Tyryshkin, S.V. Baranov and G.C. Dismukes,
  Bicarbonate participates in the assembly of the tetra-Mn Cluster in Photosystem II: pH dependence of Mn3+ EPR signal,
  Appl. Magn. Reson. (2010) 37, 137–150
• R. Frontiera, J. Dasgupta and R.A. Mathies,
  Femtosecond Raman structural studies of photoinduced electron transfer at a dye/semiconductor interface;
  J. . Am. Chem. Soc. (2009) 131, 15630-2
• K. Spillane, J. Dasgupta, J. C. Lagarias and R. A. Mathies,
  Homogeneity of Phytochrome Cph1 Vibronic Absorption Revealed by Resonance Raman Intensity Analysis,
  J. Am. Chem. Soc. (2009) 131, 13946–13948
• S. Shim, J. Dasgupta and R.A. Mathies,
  Femtosecond Time-Resolved Stimulated Raman Reveals the Birth of the J and K Intermediates in Bacteriorhodopsin’s Photocycle,
  J. Am. Chem. Soc. (2009) 131, 7592–7597
• J. Dasgupta, R. Frontiera, K. Taylor, J.C. Lagarias, R.A. Mathies,
  Ultrafast Excited State Isomerization in Phytochrome Revealed by Femtosecond Stimulated Raman Spectroscopy,
  Proc. Natl. Acad. Sci USA (2009) 106, 1784-1789.
• J. Dasgupta, G.M. Ananyev and G.C. Dismukes,
  Photoassembly of the Water-Oxidizing Complex in Photosystem II,
  Coord. Chem. Rev. (2008) 252(3-4), 347-360.
• J. Dasgupta, A.M. Tyryshkin and G.C. Dismukes,
  ESEEM Spectroscopy Reveals Carbonate and N-donor Protein Ligand Binding to Mn²⁺ in the Photoassembly Reaction of the Mn4Ca cluster in Photosystem II,
  Angew. Chem. Int. Ed. (2007), 46, 8028-8031
• A.M. Tyryshkin, R. Watt, S.V. Baranov, J. Dasgupta, M. Hendrich and G.C. Dismukes,
  Ca²⁺ Directs the Assembly of the Mn₄Ca Cluster in the Photosynthetic Water Oxidizing Complex: Formation of a Ligand Bridge to Mn³⁺ via Deprotonation,
  Biochemistry (2006), 45, 12876-12889.
• J. Dasgupta, A.M. Tyryshkin, Yu.N. Kozlov, V.V. Klimov and G.C. Dismukes,
  Carbonate complexation with Mn²⁺ in Aqueous Phase: Redox Behavior and Ligand Binding Modes by Electrochemistry and EPR,
  J. Phys. Chem. B (2006), 110, 5099-5111.
• G.C. Dismukes, V.V. Klimov, S.V. Baranov, Yu. N. Kozlov, J. Dasgupta, and A.M. Tyryshkin,
  The Origin of Atmospheric Oxygen on Earth: The Innovation of Oxygenic Photosynthesis,
  Proc. Natl. Acad. Sci. USA (2001), 98, 2170–2175.

• Femtosecond Stimulated Raman Spectroscopy in Encyclopaedia of Biophysics Ed. by Prof. Andreas Barth, to be published in 2013.