Simultaneous measurement of rotational and translational diffusion by forced Rayleigh scattering. Colloid spheres in suspension

It is shown that the technique of forced Rayleigh scattering, traditionally employed to probe translational diffusion, can be employed to probe rotational diffusion as well. Thus with a single experiment both quantities are measured. The system under investigation is colloid spheres suspended in a glass-forming liquid. Furthermore, it is shown that the Stokes-Einstein and Debye-Stokes-Einstein relations for translational and rotational diffusion, respectively, are valid for spherical colloid particles in a supercooled liquid matrix in the vicinity of the glassy state.