EXAFS studies of lattice dynamics and thermal expansion

Accurate temperature-dependent EXAFS measurements can give original information on the correlation of thermal motion in crystals, not only along the bond direction (parallel Mean Square Relative Displacement, MSRD), but also within the perpendicular plane (perpendicular MSRD). This potential is demonstrated by the results obtained for copper and germanium, taken as model systems. Possible applications for investigating on the local origin of Negative Thermal Expansion are being supported by measurements on crystals with the cuprite structure.