Physical chemistry focuses on understanding the physical basis of chemical phenomena. This goal is pursued through the concerted efforts of experimentalists and theorists. While experimentalists design and carry out laboratory investigations of chemical systems, theorists conceive and develop theoretical tools to explain and predict system properties. Physical chemistry provides the fundamental scientific tools to investigate systems of interest in a wide range of disciplines, including engineering and biology.
At the University of Oregon, research in physical chemistry focuses on a variety of topics. Research in spectroscopy comprises theoretical quantum mechanical approaches as well as experimental techniques.
On the theoretical front, studies in semiclassical and quantum mechanics include the dynamics of highly excited molecules (Kellman) to interpret experimental spectra and unravel mechanisms to model internal molecular energy flow and investigate fundamental issues in reaction dynamics, such as the nature of the reaction coordinate and transition state; the development of a formal description of wavepacket interferometry (Cina) to gain direct experimental information at the level of time-dependent quantum mechanical wave functions; and the elucidation of molecular structure through theoretical studies of electronic potential energy surfaces (Herrick).
Work in experimental spectroscopy includes a number of novel techniques developed at the University of Oregon:
1) Pulsed laser techniques to probe the molecular structure at wet interfaces involving a liquid in contact with air, solids, or other immiscible liquids (Richmond).
2) New optical techniques including FICS to study the motions of intracellular species in cellular compartments as well as macromolecules in liquids; and fluorescence-detected multi-dimensional electronic spectroscopy to study the dynamics of excited states in molecules and how they interact with their local environments (Marcus).
3) A conceptually different spectroscopic approach, capable of providing spectrocopic information on the atomic scale, is based on Scanning Tunneling Microscopy. The ultra-fine spatial resolution of this technique is used to investigate the surface chemistry of novel nanomaterials, as well well as chemical processes occuring on the single-molecule scale (Nazin). A new focus area is quantum control where we investigate theoretically (Cina) how wavepacket interferometry can be used as a form of analogue computation to the experimentally determined (Marcus) evolution of nuclear wave functions of molecules, as driven by a short laser pulse of arbitrary temporal shape.
4) Non-linear spectroscopic techniques are used to measure electronic structure and exciton dynamics in non-equilibrium systems. Many non-equilibrium processes are not well understood, such as the self-assembly of nanoparticles, and the formation of thin films from solutions of small molecules or polymers. Understanding how electronic properties evolve during these processes enables the tailoring of environmental conditions for designer materials properties (Wong).
Theoretical (Guenza) and experimental (Marcus) studies in statistical mechanics of soft condensed matter and complex fluids focus on the investigation of structure and dynamics of complex molecular systems in the liquid phase (macromolecules and colloids). Understanding and predicting the behavior of these systems is of interest for engineers (plastics, fibers, and other viscoelastic materials) as well as for biologists for whom complex systems of interest include proteins, nucleic acids, and protein-protein aggregates such as cellular filaments.
For those systems physical chemistry extends into the realm of biophysics including different levels of coarse graining: from the submicroscopic electronic energy transfer studies of the photophysical processes underlying biochemical energy-generation in photosynthesis (Cina), to the correlation between conformational structure and biological activity in signal transduction proteins and molecular motors (Guenza), to the dynamics of intracellular species in living cells (Marcus).
Research in bioanalytical and biophysical chemistry at the nanoscale (Prell) reveals how chemical interactions give rise to preferred topologies of biomolecular assemblies and membranes and how these interactions play a role in nanoscale processes such as toxin translocation.
The physics of chemical systems at interfaces includes spectroscopic studies of organic, inorganic, and biomolecules at surfaces and interfaces (Richmond) as well as electrochemical and electrical investigations of charge transfer at molecular or nanoparticle-based semiconducting interfaces (Lonergan). Research on semiconductor interfaces aims at identifying and controlling novel systems that enhance and/or mimic the behavior of conventional semiconductor interfaces. The focus is to understand how the unique chemistry of “new” materials manifests itself in interfacial charge transfer processes.