Molecular dynamics simulation of aerogel silica on parallel computers

Molecular dynamics (MD) simulations of porous silica, in the density range 2.2-0.1 g/cm3, are carried out on a 41,472 particle system using two- and three-body interatomic potentials. Calculated results for fractal dimension and small-angle neutron scattering data are in good agreement with neutron scattering experiments. Results for structural correlations reveal crossovers from the short- to intermediate range (<8 angstroms) and fractal to large-scale regime (10 to approximately 100 angstroms). The MD program simulations are carried out on distributed-memory MIMD computers using a domain-decomposition algorithm. The algorithm employs the linked-cell-list method and separable three-body force calculation. The force calculation is accelerated by the multiple-time-step method. The parallel algorithm is highly efficient (parallel efficiency = 0.974), as it involves only 3% communication overhead.