Research Interests

PROBING MOLECULAR STRUCTURE & INTERACTIONS AT SURFACES AND INTERFACES

The surface of a medium whether it be a liquid or a solid has very special properties which are often quite distinct from the bulk substance. The surface of water for example has a very high surface tension which allows more dense objects than the bulk water to float on top of it. The surface of a semiconductor can have very different electronic properties than the bulk due to the molecular orbitals of the surface atoms which are left "dangling" as the bulk lattice is terminated.

Understanding how molecules adsorb and react with these surfaces has been of interest to surface scientists for several decades now. The challenging aspect of this surface work is always one of sensitivity, ie. how to distinguish the properties of the atomically thin surface layer from the overwhelming properties of the bulk substance. In the past two decades much progress has been made in understanding how molecules adsorb at solid surfaces and the electronic properties of such surfaces under well-controlled conditions, ie. conducting the experiment in a vacuum chamber of very low ambient pressure. Much less progress has been made at understanding surface interactions on a molecular level where solid surfaces are in contact with another condensed phase such as a liquid. This is where our interest lies.

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THE RESEARCH OF THE RICHMOND LAB IS FOCUSED IN SEVERAL GENERAL AREAS:

We have a wide range of topics currently under exploration in our laboratory. One set of studies seek to understand how water molecules hydrogen bond at a water surface and how this hydrogen bonding which is so strong at a water surface, is perturbed by the presence of solutes, surfactants and organic liquids at the surface. In our environmentally oriented projects, we are learning how atmospherically important molecules adsorb and react at the surface of water or a brine solution. In the area of material science, we are studying the interaction of aqueous media with minerals, oxides, polymers and semiconductors. These studies provide in-situ information about corrosion, processing, dissolution and adsorption at the water/solid junction. We have an extensive effort in understanding molecular processes at an oil/water interface, or related interfaces between water and an immiscible liquid. By studying alkyl surfactants, many of which are prevalent in commercial products, we attempt to understand how their molecular structure might predict their functional use. We are also interested in how biomolecules adsorb and assemble into macromolecular structures at liquid surfaces, how water interacts with these macromolecules to induce molecular conformation, and the mechanism of water and ion penetration into biomolecular assemblies.

Research Sponsored by: National Science Foundation, Office of Naval Research, Department of Energy, American Chemical Society Petroleum Research Fund