Curriculum Vita

Research: The further development of single-crystal diffraction techniques for in-situ studies of minerals at high pressures. As a result of previous technical developments (see below) the evolution of unit-cell parameters of crystals at high pressure can now be routinely measured to 1 part in 30,000. No significant further improvement can be expected. We can now measure extremely subtle changes in cell parameter evolution at high pressures, but are unable to determine the underlying reasons for such changes in the evolution of the crystal structure (i.e. in bond lengths and angles) because crystal structures cannot be determined sufficiently precisely at high pressures. We are now pursuing technical developments at VPI Crystallography Lab aimed at improving the quality of high-pressure structure refinements.

These technical developments are driven by the need to understand the structural basis for the complex compression behaviour observed at high pressures in framework structures including feldspar and perovskites. High-pressure studies on the phase transitions in ferroelastic, ferroelectric and co-elastic materials will build on my previous work in Bayreuth with the aim of understanding the fundamental physics of such transitions, and their relation to phase transitions at high temperature.

Research: The development of single-crystal diffraction techniques, especially cell parameter measurements, for in-situ studies of minerals at high pressures. At Bayreuth my collaborators and I improved the precision with which cell parameters can be determined at high pressure by apporximately an order of magnitude. This allowed the detailed determination of the high-pressure behaviour of minerals, including feldspars, pyroxenes, amphiboles, and perovskites, and the characterisation of non-quenchable high-pressure phase transitions, crossovers, and compression mechanism changes in these materials.

Research: The determination of feldspar bulk moduli by in-situ high-pressure single-crystal diffraction. The characterisation of non-quenchable displacive phase transitions in anorthite and alkali feldspars at high pressures, including the influence of Al,Si disorder. The characterisation of the compression behaviour and phase transitions in (Mg,Fe)SiO₃ pyroxenes at pressures to 8.5 GPa.