Thermodynamics tells us that spontaneous processes are ones that take matter from a state of high chemical potential to a lower one. Thermodynamics also tells us that there are two tendencies that drive spontaneous processes: systems want to go to the lowest overall energy, but they also want to increase their entropy. My principal research projects aim to increase our understanding of how these two factors play out, on a molecular level, in stabilizing one phase of matter over another. In recent years we have participated in interdisciplinary projects studying materials that exhibit negative thermal expansion (they shrink when heated and expand when cooled), that are frustrated in their ability to order magnetically, or that form complex, open-framework networks useful for catalysis or separations of materials.

Currently, members of my research group are working on projects to study nanoparticles, particles with dimensions of a few nanometers. Given their size, such particles contain a relatively small number of molecular units, and they often have very different properties from those of the bulk material of the same chemical composition. An important question is to what extent the different behavior is due to the increased contributions of energetic surfaces because of the greater surface/volume ratio in nanoparticles and/or to differences on the interior of the particle associated with finite size effects.

There are some common elements to research projects in my laboratory, efforts which are shared with my BYU Colleague, Prof. Brian Woodfield and with a colleague at the University of California at Davis, Prof. Alexandra Navrotsky. These are illustrated in the figure on the right. Each project is very interdisciplinary, involving some mix of the traditional areas of physical, inorganic and analytical chemistry. Students who graduate from my laboratory have the opportunity to use a variety of synthetic techniques to prepare materials, to become skilled in cutting-edge analytical tools to characterize those materials, and to study those materials using thermophysical (heat capacity measurements from 0.6 to 800 K at BYU) and thermochemical (reaction calorimetry at Davis) techniques to probe the balance between entropic and energetic factors. Some details of our laboratory facilities are described at the link below. A good balance is also achieved with theory and experiment, because we often model our results with theoretical calculations. The actual mix of what happens in a specific project is tailored to the needs of a project and the interests of the student. In separate links below, we present summaries of two of our recent and on-going projects.

Energetics of Nano-CoO

Magnetic Heat Capacity of Single Crystal CoO

Laboratory Facilities