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The central focus of research in Professor Pearson's lab is the use of X-ray diffraction to determine structural and electronic properties of molecules. There are three distinct aspects of this work. The first area of interest is the determination of molecular structure using the diffraction of X-rays from single crystals. This is accomplished through the use of a modern single crystal diffractometer which is available in the Chemistry Department. This instrument allows a researcher to collect diffraction data from a single crystal of a compound. Crystallographic techniques and computer analysis are then used to determine the relationship between the diffraction pattern of the crystal and the structure of the molecular units of which the crystal is made. Since the result of an X-ray study is the position of atoms in a molecule, it is a most powerful means of chemical analysis. Diffraction of X-rays by crystals is a result of the interaction of X-rays with the electron density of the crystal. If extremely accurate measurements are made of the diffraction of X-rays from a crystal, it is possible to examine the valence bond density of the molecular units. A researcher can actually record electron densities that are characteristic of chemical bonding. A main area of interest of Professor Pearson's is the determination of d-orbital electron density in transition metal oxy-anions. To complete the study of electron density distributions in chemical compounds, one must have some theoretical calculations to compare. A third area of interest is the use of molecular orbital calculations to model the electron density in compounds of interest and compare the theoretical densities with those determined by X-ray analysis. Anyone interested in this type of work should have a strong desire to probe nature for the fundamental nature of chemical bonding. An interest in instrumental analysis and chemical computing is also required. |
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