The Molecular Theory Group provides theoretical and molecular modeling support for the researchers in the Department of Chemistry and Geochemistry and in the Materials Science Program. However some of the MTG’s original research involves the use of quantum chemical methods to uncover the atomic scale mechanisms responsible for a material’s macroscopic properties. As an example, a problem that continues to interest us is that of fracture. When a material, say a piece of steel, is subjected to a load it can respond in one of three ways: it can undergo elastic deformation (when the load is removed the metal will return to its original shape), plastic deformation (the metal’s shape is permanently changed), or it can break. What is going on inside the material that determines these behaviors?
At one level, aspects of this problem are understood. Metallurgists know that a material responds plastically when the stress level is sufficient to start internal defects called dislocation moving. Hence, a metal deforms plastically when the applied stress starts these dislocations moving. But what is it that determines the stress levels at which dislocations move? When it comes to understanding the mechanism at this level, we know only that it has something to do with the movement of the electrons holding the material together. Thus, our research is concerned with explaining and predicting how a molecule or material’s electrons move when chemically or mechanically perturbed.
Of all the molecular disciplines (chemistry, materials science, condensed matter physics) organic chemistry has developed the most robust formalism to predict the movement of electrons. In part, this is why organic chemists are able to design and produce polymers and drugs with desired properties. Unfortunately, this formalism is highly restrictive and has not been applied widely in the general design of molecules and solids. So, our research often concerns generalizing the rules and principles of organic chemistry and applying them to phenomena that are not typically considered chemical in nature—such as fracture.
The MTG’s supported research programs are:- Design Research Tools: Supported by the Office of Naval Research, this program’s objectives are to develop modeling tools that will aid in materials design. Our challenge is to describe the charge density as a set of fundamental topological units called irreducible bundles and to relate the properties of materials to the packing of these units.
- Predictive Models to Aid in Design of Membrane Systems for Organic Micropollutants Removal: Supported by the Water Reuse Foundation, we are using statistical methods in combinations with quantum mechanical calculations to develop a model predicting the interaction between organic pollutants and the reverse osmosis membranes used in water purification.
- Clean Coal Technologies: Supported by Department of Energy, the MTG is one of several groups at CSM developing new materials that will make it possible to use coal as a green energy resource.