J.W. Eastwood

Bio: J.W. Eastwood is an academic researcher from University of Reading. The author has contributed to research in topics: Particle & Range (particle radiation). The author has an hindex of 1, co-authored 1 publications receiving 81 citations.

Interionic potentials in alkali halides and their use in simulations of the molten salts

Abstract: After an outline of work on rare-gas systems, which serves as a target for parallel work on alkali halides, and an initial brief survey of those parts of this parallel work for which results have been obtained, interionic potential models for alkali halides are considered in some detail. The rigid ion potentials of Fumi and Tosi are discussed and then a major part of the section is devoted to deriving a new set of polarizable ion potentials, which incorporate the ideas behind the lattice dynamical shell model. Extensions which include many-body terms in the potentials are considered briefly and finally the information which can be obtained from alkali halide diatomic molecules is discussed. In the third section methods of computer simulation for ionic liquids are outlined, concentrating on the molecular dynamics method, and some of the properties which can be obtained by analysing the ion trajectories are listed. Results from simulations, including some new work on LiF, NaCl and RbI, are reviewed.

Multiscale flow simulations using particles

Abstract: ▪ Abstract Flow simulations are one of the archetypal multiscale problems. Simulations of turbulent and unsteady separated flows have to resolve a multitude of interacting scales, whereas molecular phenomena determine the structure of shocks and the validity of the no-slip boundary condition. Particle simulations of continuum and molecular phenomena can be formulated by following the motion of interacting particles that carry the physical properties of the flow. In this article we review Lagrangian, multiresolution, particle methods such as vortex methods and smooth particle hydrodynamics for the simulation of continuous flows and molecular dynamics for the simulation of flows at the atomistic scale. We review hybrid molecular-continuum simulations with an emphasis on the computational aspects of the problem. We identify the common computational characteristics of particle methods and discuss their properties that enable the formulation of a systematic framework for multiscale flow simulations.

Multiple time-step methods in molecular dynamics

Abstract: A new method for molecular dynamics computer simulations, called the multiple time-step (MTS) method, is described, in which two or more time steps of different lengths are used to integrate the equations of motion in systems governed by continuous potential functions. With this method computing speeds have been increased by factors of three to eight over conventional molecular dynamics methods in simulations of monatomic and polyatomic fluids, with only marginal increases in computer storage.

Optimisation of the Ewald Sum for Large Systems

Abstract: Techniques are described for optimising the Ewald sum in the simulation of systems containing large numbers of charged particles. Expressions are given for the best choice of parameters to maximise performance for a specified accuracy. The algorithm for the real-space sum uses a “small-cell” version of the link-cell method. Various other computational details are discussed. In the simulation of real systems there is considerable scope for speeding the calculation by redcing cutoffs, without loss of accuracy.