Molecular dynamics simulations of vitreous silica structures

Silica molecular dynamic force fields—A practical assessment

“…All force fields except the soft potential from Takada 21 give Bulk moduli that are too high by ~ 30-40%. contributions.…”

“…They include three previously published force fields 3 14 21 and an empirical pairwise force field used by one of the authors 9 .…”

Atomistic and electronic structures of functional disordered materials revealed by a combination of quantum-beam measurements and computer simulations

“…The second peak observed at about 3.7 ¡ can be assigned mainly to ZrZr correlation, and the contribution of OO correlation is unclear owing to its small weighting factor for X-rays. The ZrO correlation length of 2.1 ¡ is significantly longer than those of SiO (³1.63 ¡ 27) at 16002100°C) and AlO (³1.78 ¡ 17) at 2127°C) owing to substantial differences between the ionic radii of silicon, aluminum, and zirconium ions. The increased cation-oxygen correlation length in l-ZrO 2 suggests that the oxygen coordination number around zirconium is higher than four because 2.1 ¡ is close to the sum of the ionic radii of oxygen (1.35 ¡) and sixfold zirconium (0.72 ¡).…”

“…(A) BhatiaThornton number-number partial structure factor S NN (Q) for l-ZrO 2 at 2800°C derived from the DFT-MD simulation (bold curve) 16) in comparison with those for l-Al 2 O 3 at 2127°C (solid curve) 17) and l-SiO 2 at 2100°C (dotted curve). 27) The momentum transfer Q was scaled by r AX (r AX is the first coordination distance between A and X in the real-space function) to eliminate the effect of the size of cations. (B) Coordination number distribution of oxygen around the cations in l-ZrO 2 at 2800°C, 16) l-Al 2 O 3 at 2127°C, 17) and l-SiO 2 at 2100°C.…”

“…27) (C) Polyhedral connections in l-ZrO 2 at 2800°C, 16) l-Al 2 O 3 at 2127°C, 17) and l-SiO 2 at 2100°C. 27) CS, corner sharing of oxygen; ES, edge sharing of oxygen; FS, face sharing of oxygen.…”