Nouvelles evidences experimentales dans l'interpretation du spectre de diffusion Rayleigh d'un cristal plastique de succinonitrile

We have verified on 3 important points the validity of the application of the hydrodynamic theory previously used to interpret the spectra of the Rayleigh scattering in a plastic crystal of succinonitrile. (1) The half-width Γ is varying as the square of the transfer wave vector q in a domain much larger than the one studied previously (Γ = Dq²). (2) Measurement of the coefficient of thermal diffusivity and comparison with D. (3) Measurement of the Rayleigh factor and comparison with the theory.