Molecular dynamics simulation of nanoporous silica

The micro-structure and dynamical properties of nanoporous silica are inves tigated using the molecular dynamics simulation method. The porous silica o btained have densities down to 0.7 g/ml and a mass fractal dimension of 2.6 or higher. The specific surface of the porous silica is calculated and fou nd to be in agreement with adsorption experiments. The vibrational and diel ectric power spectra show an enhanced intensity in the low frequency region . The low frequency modes are characterised by a covariance matrix eigenvec tor analysis and found to correspond to cluster motion. (C) 2000 Elsevier S cience B.V. All rights reserved.