Experimental investigation of the Soret effect in acetone/water and dimethylsulfoxide/water mixtures.

The thermal diffusion behavior of acetone/water and dimethylsulfoxide(DMSO)/water mixtures has been experimentally investigated by a transient holographic grating technique named thermal diffusion forced Rayleigh scattering (TDFRS). For both systems a sign change of the Soret coefficient S(T) with varying water content has been predicted by simulations [C. Nieto Draghi et al., J. Chem. Phys. 122, 114503 (2005)]. The sign change of S(T) is confirmed by the experiment. Except for equimolar concentrations of acetone/water the agreement between the experimental and simulation data is reasonable.