A Systematic Comparison of Pairwise and Many-Body Silica Potentials

The role of many-body effects in modeling silica was investigated using self-consistent force matching. Both pairwise and polarizable classical force fields were developed systematically from ab initio density functional theory force calculations, allowing for a direct comparison of the role of polarization in silica. It was observed that the pairwise potential performed remarkably well at reproducing the basic silica tetrahedral structure. However, the Si-O-Si angle that links the silica tetrahedra showed small but distinct differences with the polarizable potential, a result of the inability of the pairwise potential to properly account for variations in the polarization of the oxygens. Furthermore, the transferability of the polarizable potential was investigated and suggests that additional forces may be necessary to more completely describe silica annealing.