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Hans D. HochheimerProfessor 
Materials at Extreme ConditionsThe interest in studies of materials at extreme pressures has increased constantly in recent years, due to the development of the diamond anvil cells. Furthermore, the amount of experimental data motivated intense successful theoretical efforts which led to a better understanding of the physics and chemistry of materials at extreme conditions. In particular, self-consistent ab initio calculations were very successful in predicting structural phase transitions at high pressures.We will use diamond anvil cells as well as large volume high pressure cells (up to 1.4 GPa) for studies of conducting polymers and incommensurate systems at high pressures.In the case of the polymer research, we will concentrate on conductivity and light scattering measurements with the aim to understand the conduction process as well as to produce better materials. The main thrust concerning incommensurate systems is to study the coupling of strain to a phase mode in the incommensurate phase using Brillouin scattering. We will study a large variety of materials which undergo a phase transition to an incommensurate phase. These studies will provide a better understanding of the coupling of acoustic phonons to excitations in the incommensurate phase, and hopefully answer the question whether under pressure anharmonic terms of higher order than cubic will contribute significantly in the incommensurate phase. |