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Assistant Professor
Ph.D. University of Colorado
B.S./M.S. IIT Kanpur
Email: vivektiwari@iisc.ac.in
Phone: +91 80 2293 2439

Welcome to Multidimensional Spectro-Imaging Group

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Our group develops spectroscopic techniques and quantum dynamical models to understand ultrafast energy and charge delocalization in molecular systems. Typically all projects in our group involve experimental and strong theoretical components.

The experimental impetus is to develop techniques which combine spectral, temporal and spatial resolutions, hence the term spectro-imaging. The broad impetus is to develop spectrometers which probe matter through controlled interactions with femtosecond pulses on the sub-micron lengthscales on multiple spectral dimensions. Such techniques are relevant for probing physics of exciton delocalization and dissociation occurring at the nanoscale in several physical systems. Some of our current systems of interest include organic polymers of relevance for next-generation photovoltaics, as well as biophysical systems such as photosynthetic proteins well-known for ~100% efficiency of ultrafast energy and charge transfer.

Theoretical impetus of our group is to develop toy models of energy and charge delocalization treating non-adiabatic vibrational-electronic mixing effects through numerically exact approaches. We use such Hamiltonians to simulate the spectroscopic signatures from the above experiments in order to better understand the ultrafast quantum dynamics in the system. 

Visit our group website or our laboratory to know more about our current interests.

  1. V. Tiwari, Y. A. Matutes, A. T. Gardiner, T. L. C. Jansen, R. J. Cogdell, and J. P. Ogilvie, “Spatially-resolved fluorescence-detected two-dimensional electronic spectroscopy probes varying excitonic structure in photosynthetic bacteria,” Nat. Comm. 9, 4219 (2018). Editors’ Choice
  2. V. Tiwari, Y. A. Matutes, A. Konar, Z. Yu, M. Ptaszek, D. F. Bocian, D. Holten, C. Kirmaier, and J. P. Ogilvie, “Strongly coupled bacteriochlorin dyad studied using phase-modulated fluorescence-detected two-dimensional electronic spectroscopy,” Optics Express 26, 22327-22341 (2018).
  3. V. Tiwari, W. K. Peters, and D. M. Jonas, “Electronic resonance with anticorrelated pigment vibrations drives photosynthetic energy transfer outside the adiabatic framework,” PNAS 110, 1203-1208 (2013). Science Editors’ Choice, PNAS Cover Mention
  4. V. Tiwari, W. K. Peters, and D. M. Jonas, “Vibronic coherence unveiled,” Nat. Chem. 6, 173-175 (2014). News and Views.
  5. B. Cho*, V. Tiwari*, R. J. Hill, W. K. Peters, T. L. Courtney, A. P. Spencer, and D. M. Jonas, “Absolute Measurement of Femtosecond Pump–Probe Signal Strength,” J. Phys. Chem. A 117, 6332-6345 (2013). (* denotes equal authors)