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Light-scattering measurements of nonequilibrium fluctuations in a liquid mixture

1993; American Physical Society; Volume: 47; Issue: 2 Linguagem: Inglês

10.1103/physreve.47.1026

1538-4519

P. N. Segrè, Robert W. Gammon, J. V. Sengers,

Chemical Thermodynamics and Molecular Structure

We report results of small-angle Rayleigh-scattering experiments performed in an equimolar liquid mixture of toluene and n-hexane that is brought out of thermal equilibrium by the imposition of a stationary temperature gradient \ensuremath{\nabla}T perpendicular to the scattering wave vector. The experiments demonstrate the presence of long-range nonequilibrium fluctuations in temperature, concentration, and momentum and confirm that the strength of these nonequilibrium fluctuations varies with (\ensuremath{\nabla}T${)}^{2}$/${\mathit{k}}^{4}$, where k is the wave number of the fluctuations. It is suggested that nonequilibrium Rayleigh scattering may provide an alternative technique for measuring Soret coefficients of liquid mixtures.