Fig. 5: Bond and dihedral angle distributions for the MD-RMC models of glassy SiO2.
From: Structure and properties of densified silica glass: characterizing the order within disorder
A The Si–Si–Si, Si–O–Si, Si–Si–O, O–Si–O, O–O–Si, and O–O–O bond angle distributions (BADs). B The Si–Si–Si–Si, Si–O–Si–O and O–O–O–O dihedral angle distributions, where several of the curves are offset vertically for clarity of presentation. In (A) and (B), the curves correspond to RT/7.7 GPa (black), 400 °C/7.7 GPa (red), 1200 °C/7.7 GPa (blue) and RT/20 GPa (cyan). The O–Si–O BADs have a peak at ∼109° as expected for network structures built from tetrahedral SiO4 units. The Si-Si-Si BADs have a large peak at ∼109° and a smaller feature at ∼60° that originate from oxygen-decorated SiSi4 tetrahedra. Changes to the BADs are most noticeable with increasing density from RT/7.7 GPa to 400 °C/7.7 GPa (e.g., there is a shift in position and broadening of the inter-tetrahedral Si–O–Si BAD) but are relatively subtle with a further increase in the density.
