My scientific interest focusses on properties of geomaterials (and to some extent also other inorganic materials) at high temperatures and pressures, on the basis of their atomic structures and relevant to geochemistry and geophysics. These properties encompass the thermodynamic stability of minerals in order to elucidate the pressuretemperature path of natural rocks, the kinetics of intracrystalline exchange processes for estimating the uplift history of rocks, oxygen vacancies in e.g. perovskite, their clustering and the consequences for electrical properties, and short-range order in melts and glasses and their relation to properties such as viscosity and density. Mostly crystallographic problems such as the unusual structures of the compound Cr2SiO4 or the fivefold coordination of silicon in substituted titanite CaSi2O5, the incommensuratecommensurate phase transition in melilite-structured compounds have also been investigated. For these studies, methods for probing either long-range order (X-ray crystallography, also at high pressures and temperatures) and local environments (Raman and Mössbauer spectroscopies, ELNES and XANES, often in-situ) have been applied and have partly also been developed further for application at high temperature.
