Biomedical subjects

Y Rosenfeld

Publications and source records attributed to Y Rosenfeld.

At least 19 recordsLinked to original sources

PubMed2000

Predicting the liquid-vapor critical point from the crystal anharmonicity

A "universal" dependence is predicted of the reduced critical parameters, k(B)T(c) / E0(gamma), V(c) / V0(gamma), and P(c)V(c)/k(B)T(c) = Z(c)(gamma), on the crystal anharmonicity gamma (closely related to the Gruneisen parameter gamma(G)). It is based on a simplified embedded-atom type approach which enables one to utilize the universal zero-temperature equation of state in a version of fluid perturbation theory. This model's critical temperature and density agree with the experimental results for both the heavy rare gases ( gamma approximately 2.85) and heavy alkali metals ( gamma approximately 1.35). Predicted critical parameters for many other liquid metals are consistent with previous estimates, but the model is not applicable when directional bonding is important.

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PubMed2000

Structural stability of simple classical fluids: universal properties of the lyapunov-exponent measure

A threshold for the stability of the solution of integral equations for the pair correlation function of a classical fluid can be determined from the Floquet matrix for the iterative form of the integral equation. Correspondingly, a measure of the structural stability of the fluid, analogous to the Lindemann ratio for a solid, is provided by the Lyapunov exponent lambda that is related to the perturbed dynamics. The behavior of lambda as a function of density, temperature, interatomic potential, and closure relations for the integral equation, is analyzed and discussed. In analogy with the Lindemann parameter, we find-for the hypernetted-chain-type closures-that lambda(T/T(inst)) is "quasiuniversal," i.e., very weakly dependent on the interaction potential, up to a temperature T/T(inst) approximately 5, where T(inst) is the stability-threshold temperature. We show how this result connects the Lyapunov exponent measure of the pair structure with the equation of state of the fluid.

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PubMed2000

Fluid of penetrable spheres: testing the universality of the bridge functional

Penetrable spheres have been the object of recent extensive investigations as a prototype for intermicellar interactions in a solvent, and as representing a class of bounded potentials allowing complete interpenetrability of the particles. Here we compare density-functional and simulation results for the pair-correlation functions in a bulk fluid of penetrable spheres, as a stringent test for the approximation of "universality" of the bridge functional. Considering either a fundamental-measure functional for penetrable spheres or a perturbative treatment using a fundamental-measure hard-sphere functional, we conclude that hard-sphere-type bridge functionals are applicable also for bounded potentials with high penetrability.

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PubMed2000

Excess-entropy and freezing-temperature scalings for transport coefficients: self-diffusion in yukawa systems

A semiempirical "universal" corresponding states relationship, for the dimensionless transport coefficients of dense fluids as functions of the reduced configurational entropy, was proposed more than 20 years ago and established by many simulations. Recent density functional analysis predicts a universal freezing-temperature scaling for the excess entropy. Combining these properties we derive an approximate corresponding states relationship for the dimensionless transport coefficients of dense fluids as functions of the temperature scaled by the freezing temperature. The temperature scaling observed in recent computer simulation results for self-diffusion in Yukawa systems is just one more case of our general result.

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PubMed1996