Real-Time Chemical Reactions and Structural Changes
We observe chemical reactions and structural changes in natural and artificial systems while they take place. We probe advanced 2D materials, metal complexes and metalloproteins, to understand their transformations and how they function. Ultrafast pulses from X-ray lasers and lab sources give us the high-speed X-ray vision to watch the inner workings of electrons, atoms, and molecules in real time.
Excited State of Mo-Se2
Depiction of an optical femtosecond laser excitation initiating the ultrafast non-radiative dynamics in an Mo-Se2 atomic bilayer
Photosynthesis in action
The Kok cycle of photosynthesis, where plants use the energy from sunlight to split water, providing the oxygen we breath
Dynamics in 2H-Mo-Te2
XUV transient absorption showing the simultaneous carrier and hole dynamics in real time
Dynamics in 2H-Mo-Te2
Carrier-specific dynamics in 2H-MoTe2 observed by femtosecond soft X-ray absorption spectroscopy at the Pohang X-ray laser
Dynamics in 2H-Mo-Te2
Schematics of femtosecond XUV absorption spectroscopy probing the redistribution of electrons and holes after optical excitation
Selected Publications
Ash et al, X-FAST: A versatile, high-throughput, and user-friendly XUV femtosecond absorption spectroscopy tabletop instrument, Rev Sci Instrum 94, 073004 (2023) pdf
Bhowmick et al, Structural evidence for intermediates during O2 formation in photosystem II, Nature 617, 629–636 (2023) pdf
Bergmann et al, Using X-ray free-electron lasers for spectroscopy of molecular catalysts and metalloenzymes, Nature Reviews Physics (2021) pdf
Attar et al, Simultaneous Observation of Carrier-Specific Redistribution and Coherent Lattice Dynamics in 2H-MoTe2 with Femtosecond Core-Level Spectroscopy, ACS Nano 14, 11, 1529 (2020) pdf
Kern et al, Structures of the intermediates of Kok’s photosynthetic water oxidation clock, Nature, 563, 421-425 (2018) pdf
Lin et al, Ultrafast non-radiative dynamics of atomically thin MoSe2, Nature Communications, 8, 1745 (2017) pdf
Mara et al, Metalloprotein entatic control of ligand-metal bonds quantified by ultrafast x-ray spectroscopy, Science, 356, 1276 (2017) pdf
Kern, Simultaneous Femtosecond X-ray Spectroscopy and Diffraction of Photosystem II at Room Temperature, Science, 340, 491-495 (2013) pdf
In The News
May 3, 2023
Researchers capture elusive missing step in the final act of photosynthesis SLAC Press Release ; US today news/; Yahoo!life
May 20, 2020
Untangling a key step in photosynthetic oxygen production | SLAC News
November 7, 2018
How Plants Produce Oxygen Revealed by ‘Tour-de-Force’ Laser Measurement | Gizmodo
November 27, 2017
Controlling 2D Materials with Light | SLAC News