Showing papers by "Peter T. Cummings published in 1982"
TL;DR: In this paper, a detailed study is made of the atom-atom correlation functions, especially the direct correlation function, for the interaction site model (ISM) of Andersen and Chandler, and new compressibility theorems in terms of the site-site direct correlation functions are derived.
Abstract: A detailed study is made of the atom-atom (i.e. site-site) correlation functions—especially the direct correlation function—for the interaction site model (ISM) of Andersen and Chandler. The work is based on the observation of Hoye and Stell that the site-site Ornstein-Zernike-like equation of Chandler and Andersen can be regarded as a rewritten version of the usual Ornstein-Zernike equation for particle-particle correlations, where the particles are identified with the atoms that constitute the ISM molecules. Our new results include (i) new compressibility theorems in terms of the site-site direct correlation functions, and (ii) for ISM diatomics (both polar and non-polar) full asymptotic (i.e. large-r) characterization of the site-site direct correlation function based on the assumption that the corresponding particle-particle direct correlation function behaves asymptotically like the particle-particle potential times -1/k B T (k B = Boltzmann's constant and T = absolute temperature). Further asymptoti...
106 citations
TL;DR: In this paper, Monte Carlo simulation results for the dielectric constant of the polar hard dumb-bell fluid are presented, where the Ewald sum technique is used to take account of the long range nature of the electrostatic interactions.
Abstract: We present Monte Carlo simulation results for the dielectric constant of the polar hard dumb-bell fluid The Ewald sum technique is used to take account of the long range nature of the electrostatic interactions The results for the dielectric constant are found to be sensitive to the choice of the dielectric constant of the continuum which surrounds the simulation sample We include comparisons with experimental results on chloromethane and the predictions of an analytically solvable approximation for the polar hard dumb-bell fluid
35 citations
TL;DR: In this article, the exact asymptotic form of the site-site direct correlation function for linear triatomic molecules for linear linear triplets has been studied, and the authors present an exact site site direct correlation model for linear triplet molecules.
Abstract: (1982). Exact asymptotic form of the site-site direct correlation function for linear triatomic molecules. Molecular Physics: Vol. 46, No. 3, pp. 665-670.
19 citations
TL;DR: In this article, the authors present evidence that the observed experimental behaviour could be explained in terms of the density-dependent Friedel oscillations in the effective inter-ion potential for rubidium.
Abstract: Recent experimental results on liquid rubidium have demonstrated agreement between derivatives of the structure factor with respect to density and momentum transfer as predicted by the uniform fluid model. Using a selection of model fluids (the hard-sphere fluid, the Yukawa fluid and a simplified model of liquid metals), each of which is solvable analytically within the mean spherical approximation, the authors present evidence that the observed experimental behaviour could be explained in terms of the density-dependent Friedel oscillations in the effective inter-ion potential for rubidium.
14 citations
10 citations
TL;DR: In this paper, the authors present new work on this problem for densities near 1 × 1027 atoms/m3 for noble gases, where the pair and three body forces in noble gases are modeled using the virial series.
Abstract: In order to study the pair and three body forces in noble gases it is important to understand the behaviour of the virial series for g(r) and to have reliable computer simulations of states at low densities Questions have arisen as to the accuracy of such calculations and in this paper we present new work on this problem for densities near 1 × 1027 atoms/m3
6 citations
TL;DR: In this article, some properties of the Boltzmann equation for a spatially uniform system of Maxwellian molecules are considered, including the explicit evaluation of the energy-space transition probability P ( y, z ; x ), the expression of the constants λ n and μ n,i which enter in the moment equations, the form of energy BE, the linearization of the moment equation, and a symmetry property of the BE itself.
Abstract: Some properties of the Boltzmann equation (BE) for a spatially uniform system of Maxwellian molecules are considered, including the explicit evaluation of the energy-space transition probability P ( y , z ; x ), the evaluation of the constants λ n and μ n,i which enter in the moment equations, the form of the energy BE, the linearization of the moment equations, and a symmetry property of the BE itself.
4 citations