Mission Statement

Chemical reactions involve the rearrangements of atoms, the breaking of bonds and the formation of new ones. At the atomic level, such motions occur on time scales as short as a few tens of femtoseconds ( 1 fs = 10^-15 s ). We are using spectroscopic techniques that are able to temporally resolve such incredibly fast events and at the same time, are sensitive to the molecular structural changes accompanying the elementary chemical process.

In particular, femtosecond nonlinear spectroscopy in the ultraviolet, the visible, and the infrared spectral regions are used to exploit the time-dependent molecular-optical properties that are associated with chemical transformations. We are interested in reactive processes such as light-triggered dissociations, proton and electron transfer reactions, and conformational isomerizations. In addition, we explore non-reactive dynamics such as intermolecular vibrational energy transfer, intramolecular vibrational redistribution, electronic dephasing and time-dependent solvation.

To this end, we implement in our laboratories novel techniques of femtosecond electronic and vibrational spectroscopies such as rapid-scan time and frequency-resolved transient absorption, fluorescence upconversion, IR and VIS photon echoes, Raman-induced optical Kerr effect and femtosecond nonlinear infrared spectroscopy. Such tools are being supplemented by single-molecule methods like confocal fluorescence lifetime imaging and fluorescence correlation spectroscopy.

We are particularly interested in observing chemical dynamics in hydrogen-bonded systems and in disclosing the influence of hydrogen-bonding on chemical reactivity. The hydrogen-bonded systems we focus on range from simple molecular liquids such as water and aqueous solutions to highly complex supramolecular architectures. Hydrogen-bonded liquids are studied under a wide variety of thermodynamic conditions ranging from nanoscopic liquid droplets with interfaces to soft matter, to bulk liquid and supercritical phases at elevated pressures and temperatures. Supramolecular hydrogen-bonded architectures are being fabricated artificially by our synthetically oriented project partners using advanced methods of organic and inorganic synthesis.

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