Determination of the Structure and Thermodynamics of Square Well Potential From the Tail of the Direct Correlation Function

Following Stell, one can determine the pair correlation function h(r) of the hard sphere fluid for all distance r by specifying only the tail of the direct correlation function c(r) at separation greater than the hard core diameter σ . More recently, Katsov and Weeks extended Stell ideas to describe the structure of continuous fluids containing repulsive and attractive parts like Lennard-Jones and Yukawa fluids. In this paper, we extend these ideas to determine the structure and thermodynamics of square well potential from the tail of the direct correlation function. This potential is used essentially to model complex systems like polymers and colloids. We use the Martinov-Sarkisov bridge functions in the closure relation. An efficient numerical algorithm is used based on Labick procedure. We give results for the structure and thermodynamics at different values of the width of the square well potential, and at different thermodynamical states.Following Stell, one can determine the pair correlation function h(r) of the hard sphere fluid for all distance r by specifying only the tail of the direct correlation function c(r) at separation greater than the hard core diameter σ . More recently, Katsov and Weeks extended Stell ideas to describe the structure of continuous fluids containing repulsive and attractive parts like Lennard-Jones and Yukawa fluids. In this paper, we extend these ideas to determine the structure and thermodynamics of square well potential from the tail of the direct correlation function. This potential is used essentially to model complex systems like polymers and colloids. We use the Martinov-Sarkisov bridge functions in the closure relation. An efficient numerical algorithm is used based on Labick procedure. We give results for the structure and thermodynamics at different values of the width of the square well potential, and at different thermodynamical states

Crossover Frequency and Transmission-Line Matrix Formalism of Electromagnetic Shielding Properties of Laminated Conductive Sheets

This paper proposes an approach to calculate the crossover frequency of each layer in the multilayered shield and subsequently that of structure constructed by n layers. This important frequency provides a useful approximation for field penetration in a conductor. It is used in a wide variety of calculations. It is in this context that a simplification of the transmission-line matrix formalism for laminated conductive sheets is done using this frequency. Two ranges of frequency are considered: lower and higher than the crossover frequency. Simples formulas and easy to use of the reflection loss, the internal reflection, the absorption loss and the electromagnetic shielding effectiveness of laminated shield are obtained. Analysis is carried out for the study of two shields: i) single shield of carbon nanotube polymer composites (CNTs), ii) multilayered shield constructed with Nickel–carbon nanotube polymer composites–Aluminum (Ni–CNTs–Al)

Velocity autocorrelation function of a Brownian particle

In this article, we present molecular dynamics study of the velocity autocorrelation function (VACF) of a Brownian particle. We compare the results of the simulation with the exact analytic predictions for a compressible fluid from [6] and an approximate result combining the predictions from hydrodynamics at short and long times. The physical quantities which determine the decay were determined from separate bulk simulations of the Lennard-Jones fluid at the same thermodynamic state point.We observe that the long-time regime of the VACF compares well the predictions from the macroscopic hydrodynamics, but the intermediate decay is sensitive to the viscoelastic nature of the solvent.Comment: 7 pages, 6 figure

Trace diffusion in a simple liquid

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How reliable is the HMSA integral equation for the pair structure of supercooled and amorphous mixtures?

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