Research Topics
Experimental Methods
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Fayer Lab Research Overview
The Fayer Group is interested in the problem of how to
experimentally examine fast molecular processes that are occurring
under thermal equilibrium conditions. A vast
amount of chemistry occurs at or near room temperature in the ground
electronic state of molecules. From synthetic organic chemistry to
biological chemistry, chemical processes occur on fast time scales.
Although the rate of an overall process may be slow, key events on
the molecular level are fast. For example, in a second order
reaction, the rate of the reaction can be controlled by the
diffusion of the species into contact, but the actual reactive event
occurs on a very fast time scale. The binding of a substrate to an
enzyme can be very slow, but the structural changes of the enzyme or
the reaction of the substrate once the substrate finds its way into
the binding site can be very fast. We are developing and applying
new experimental and theoretical approaches to the study of
important chemical processes. Why do we want to study fast molecular dynamics? On Earth, an
enormous fraction of molecular processes in chemistry, biology, and
materials science occur at or near the room temperature. These processes
are driven by the thermal energy contained in the systems. They
occur in the ground electronic state rather than through promotion
to a high energy state by the absorption of light. While there are
important chemical systems that are driven by the absorption of
light, for example, the initial step in photosynthesis, most
chemistry occurs through the dynamics induced by ambient thermal
energy. But why should we be interested in fast molecular dynamics?
Molecules are small. Therefore, the intrinsic time scale for
molecular motions is very fast, on the order of picoseconds (ps),
10-12 seconds. Fundamental steps in molecular processes occur on
very fast time scales. Slow processes, which are frequently observed
in chemistry and biology, occur through sequences of very fast
steps. Furthermore, as mentioned above, most chemistry and biology
are driven thermally, that is by the heat that is present in systems
at ambient temperatures. Therefore, understanding fast molecular
dynamics under thermal equilibrium conditions is central to
understanding the nature of the world around us. We are studying a range of interrelated problems that involve
complex systems of molecules. We are using ultrafast infrared
methods including two dimensional vibrational echo and polarization
selective pump probe experiments, ultrafast to slow optical
heterodyne detected optical Kerr effect experiments, as well as very
fast transient absorption and fluorescence measurements. We are
investigating organic liquids, particularly anisotropic
intermolecular interactions that give rise to solute-solvent
complexes. We are studying the dynamics of water in nanoscopic
systems water nanopools in reverse micelles, water nanochannels in
Nafion fuel cell membranes, water in planar systems, particularly at
the surfaces of membranes and proteins, and we are studying the
effect of charged solutes (salts) on water dynamics. We are also
studying dynamics and interaction in organic ionic liquids (so
called greens solvent), supercooled liquids, and liquid crystals. We
are also investigating how nanoscopic environment influence
important chemical processes, such a proton transfer in nanoscopic
water environments like fuel cell membranes. The following is a list of very recent review and feature articles that summarize some of our work.
Recent Reviews
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