title: Thermal diffusion in a binary liquid due to rectified molecular fluctuations.
abstract: The Soret motion in binary liquids is shown to arise to a large extent from rectified velocity fluctuations. From a hard-bead model with elastic collisions in a nonuniform temperature, we derive a net force on each molecule, which is proportional to the temperature gradient and depends on the ratio of the molecular masses and moments of inertia. Our findings agree with previous numerical simulations and provide an explanation for the thermal diffusion isotope effect observed for several liquids.
authors.affiliation: Laboratoire Ondes et Matière d'Aquitaine, Université Bordeaux 1 and CNRS, 351 Cours de la Libération, F-33405 Talence, France.
authors.forename: Simon
authors.initials: S
authors.lastname: Villain-Guillot
authors.forename: Alois
authors.initials: A
authors.lastname: Würger