Abstract :
An elastic and inelastic X-ray scattering investigation of the anomalous lattice properties of the heavy fermion compound CeRu2Si2 is reported. Thermal expansion, thermal diffuse scattering and phonon spectra were measured between 300 and 10 K. The static properties reflect the Kondo regime while no anomaly is found in the phonon dynamics. The present experiment also demonstrates the possibility of performing inelastic X-ray scattering in strongly absorbing compounds.