Excess entropy scaling for the diffusion coefficient in expanded liquid metals.
Molecular-dynamics simulation is used to compute the pair correlation function and the velocity autocorrelation function of Cs and Rb along the liquid-vapor coexistence curve, from which the excess entropy S(ex) and the diffusion coefficient D are deduced. The numerical results of both physical properties are correlated and a scaling law between the excess entropy and the reduced diffusion coefficient D(*)(=D/D(0)) is investigated for different expressions of the reduction parameter D(0). The choice of thermodynamic states along the liquid--vapor coexistence curve gives us the possibility to extend the investigation of the relation between the reduced diffusion coefficient and the excess entropy over a wide area and to test the adequacy of the scaling law confidently.
Laboratoire de Theorie de la Matiere Condensee, Universite de Metz, 1 bd. F. D. Arago, CP 87811, 57078 Metz, France. breton@dzeta.sciences.univ-metz.fr
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