Porous Silica Cluster Collision Molecular Dynamics

Silica nanoparticles are theorized to exist in the interstellar medium, where collision velocities range over several orders of magnitude. We report molecular dynamics simulation studies of the coalescence of small (approx. 2 nm) porous silica clusters with each other for a range of velocities and initial cluster porosities. Our use of the ReaxFF bond-order potential allows us to account for bond dynamics during the collision. We vary cluster porosity through the random removal of silica base units during the cluster formation stage and monitor post-collision structural dynamics. We compare both the pair correlation function and structure factors of prepared porous clusters as verification of our preparation method. We use simulation data to study the evolution of post-collision cluster morphology characterized in terms of final porosities and fractal dimensions as a function of the initial range of porosities and velocities. We compare our results with similar studies using different potentials during collision processes.