ATOMISTIC SIMULATIONS ON PARALLEL ARCHITECTURES

Algorithms are designed to implement molecular-dynamics simulations on emerging concurrent architectures. For systems with finite-range inte ractions, a domain decomposition algorithm is used to implement the mu ltiple-time-step (MTS) approach to molecular-dynamics (MD) simulations on distributed-memory multiple instructions multiple data (MIMD) mach ines. This approach reduces the computation of forces significantly by exploiting the different time scales for short-range and intermediate -range interactions. Parallel algorithms are also designed for MD simu lations of bulk Coulombic systems. The performance of these algorithms is tested on the Intel iPSC/860 system.The computational complexity o f these algorithms is O(N) and parallel efficiencies close to 0.9. Mol ecular-dynamics simulations are carried out to investigate the structu ral and dynamical properties of highly densified and also porous silic a glasses. Changes in the short-range and intermediate-range order in amorphous SiO2 are determined at different densities in the range of 4 .28-0.1 g/cm(3). Results for internal surface area and surface-to-volu me ratio in porous SiO2 are also discussed. (C) 1993 John Wiley and So ns, Inc.