Rather Research Group website

The central theme of our research program is light-matter interactions in complex energy-conversion molecular and material systems in chemistry. We harness these light-matter interactions in cutting-edge ultrafast time-resolved laser spectroscopy to explore the mechanisms of light-initiated processes in organic and inorganic molecules and materials, low-dimensional semiconducting materials, organic semiconductors, etc. informing the design of next-generation energy-conversion platforms. Our research program also seeks to selectively exploit ultrafast laser spectroscopy to alter the properties of molecules and materials with applications from solar energy to optoelectronics and catalysis to quantum information.

In our research, we use femtosecond (10^-15 seconds) optical laser pulses to unravel excited state dynamic processes including energy transfer, electron transfer, excitonic and carrier transport, structural transformations, bath reorganizations, etc. in various molecular and material systems by means of multidimensional electronic spectroscopies that implements multiple laser pulses for preparing and probing excited electronic states as a function of time.

We are also particularly interested in unraveling the role of mixed quantum degrees of freedom - electronic, vibrational, and spin - in controlling the excited state dynamics that occur on a superfast timescale. Our aim is to understand how certain quantum effects like vibronic effects, spin-vibronic effects, and wavefunction delocalizations, regulate the fate of excited state processes for solar energy conversion, photocatalysis, and quantum information.

Representative Publications

Shahnawaz R. Rather, Nicholas Weingartz, Sarah Kromer, Felix Castellano, Lin X Chen, “Spin-vibronic coherence drives singlet-triplet conversion”, Nature (2023)

Shahnawaz R. Rather, Bryan Kudisch, Bo Fo, Gregory D. Scholes, "Interplay of Quantum Vibrations During an Ultrafast Electron Transfer Reaction", Nature Chemistry, 13, 70-76 (2021)

Yusuke Yoneda, Bryan Kudisch, Shahnawaz R. Rather, Margherita Maiuri, Yutaka Nagasawa, Gregory D. Scholes, Hiroshi Miyasaka, Vibrational Dephasing along the Reaction Coordinate of an Electron Transfer Reaction. Journal of American Chemical Society, 143, 14511 (2021)

Shahnawaz R. Rather, Mate J. Bezdek, Paul J. Chirik, Gregory D. Scholes, "Dinitrogen Coupling to a Terpyridine-Molybdenum Chromophore Is Switched on by Fermi Resonance", Chem, 5, 402-416 (2019)

Shahnawaz R. Rather, Gregory D. Scholes, "From Fundamental Theories to Quantum Coherences in Electron Transfer", Journal of American Chemical Society, 141, 708-722 (2019)

Shahnawaz R. Rather, Mate J. Bezdek, Marius Koch, Paul J. Chirik, G. D. Scholes, "Ultrafast Photophysics of a Dinitrogen-Bridged Molybdenum Complex", Journal of American Chemical Society, 140, 6298-6307 (2018)

Chanelle C. Jumper,* Shahnawaz R. Rather,* Sewi Wang, Gregory D. Scholes, "From coherent to vibronic light harvesting in photosynthesis", Current Opinion in Chemical Biology, 47, 39-46 (2018) *-equal contributions

Unveiling the quantum dance: Experiments reveal nexus of vibrational and electronic dynamics- click here

Spin-conversion's Hidden Ally: Spin-vibronic coherence effect- click here

Role of Quantum Vibrations in Electron Transfer- click here

Mapping electron transfer trajectory to multiple vibrational reaction coordinates- click here

Vibrational wavepacket evolution in parallel with superfast electron transfer reaction- click here

Illuminating Fermi Resonances that Trigger Reaction in a Complex Molecule- click here

• The main approach utilized in the Rather group is a suite of ultrafast time-resolved laser spectroscopy. The various equipments based on this approach will have state-of-the-art spectral bandwidth (visible to near-infrared) and time resolution (<10 femtoseconds) with high-speed and high-sensitivity detection. Broadband pump-probe (aka broadband Transient Absorption spectroscopy, and two-dimensional electronic spectroscopy along with a pump-push-probe setup will measure the light-induced excited state energetics, structure and dynamics of chemical and materials systems over variable timescales ranging from femtosecond to picosecond to nanoseconds and more.
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• The more familiar spectroscopic tools including steady state UV-vis and near-infrared absorption, steady state and time-resolved fluorescence will also be used to characterize the excited state energetics, structure and dynamics of the chemical and material systems under investigation.
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• The samples used in our lab are mostly in the solution phase or in the form of thin films investigated at room temperature or at low-temperatures.

In the Rather group, our approach brings together aspects of chemistry, optics, spectroscopy, materials, renewables, quantum information and much more. you will obtain a comprehensive expertise in the design, construction and control of optical setups, programing for hardware and data acquisition, data analyses, electronic structure calculations, and much more. You will also get to collaborate with many research groups within the Chemistry, Materials and Medicine at the University of Kentucky, and outside.