XAFS and thermodynamic variables (pressure and temperature) to investigate matter

The importance of exploring the physical properties and phase transitions of matter under high pressure and/or high temperature are illustrated using basic thermodynamic concepts. The specific role of the X-ray absorption fine structure (XAFS) is addressed with emphasis on its unique sensitivity to the atomic short- range order. Current techniques suitable for performing high-pressure and/or high-temperature XAFS measurements are discussed. Examples of applications to elemental systems as well as perspectives and trends in innovations are briefly reviewed.