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DL_POLY_3 is a general-purpose massively parallel molecular dynamics simulation package embedding a highly efficient set of methods and algorithms such as: Domain Decomposition (DD), Linked Cells (LC), Daresbury Advanced Fourier Transform (DAFT), Trotter derived Velocity Verlet (VV) integration and RATTLE. Written to support academic research, it has a wide range of applications and can run on a wide range of computers; from single processor workstations to multi-processor computers. The code development has placed particular emphasis on the efficient utilization of multi-processor power by optimised memory workload and distribution, which makes it possible to simulate systems of the order of tens of millions of particles and beyond. In this paper we discuss the new DL_POLY_3 design, and report on the performance, capability and scalability. We also discuss new features implemented to simulate highly non-equilibrium processes of radiation damage and analyse the structural damage during such processes. have introduced the Domain Decomposition (DD) 10 version, DL_POLY_3, to permit simulation of systems of the order of tens of millions of atoms and beyond. As we shall see in the Performance and discussion section, DL_POLY_3's inherent parallelism allows close to perfect parallelisation up to impressively high processor counts.

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We present a new efficient Monte Carlo method for the molecular-based computer simulation of chemical systems undergoing any combination of reaction and phase equilibria. The method requires only a knowledge of the species intermolecular potentials and their ideal-gas properties, in addition to specification of the system stoichiometry and thermodynamic constraints. It avoids the calculation of chemical potentials and fugacities, as is similarly the case for the Gibbs ensemble method for phase equilibrium simulations. The method’s simplicity allows it to be easily used for situations involving any number of simultaneous chemical reactions, reactions that do not conserve the total number of molecules, and reactions occurring within or between phases. The basic theory of the method is presented, its relationship to other approaches is discussed, and applications to several simple example systems are illustrated.

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