The new second peak of the O-O PRDF at the high pressure originates from oxygen atoms of the edge-sharing bonds. Thus, there is rearrangement of O atoms. O atoms have tendency to more order arrangement that leads to form some oxygen hcp and fcc structure in the model at high pressure. | VNU Journal of Science: Mathematics – Physics, Vol. 34, No. 4 (2018) 77-83 Correlation between Structure Characteristics and Pair Radial Distribution Function in Silica Glass under Compression Mai Thi Lan*, Tran Thu Thuy, Le Thi Hong Lien, Le Van Vinh Hanoi University of Science and Technology Received 28 November 2018 Revised 25 December 2018; Accepted 26 December 2018 Abstract: We have studied structure of silica glass at different pressures and temperature of 300K by using Molecular Dynamics simulation (MD) method. The model consists of 6000 atoms (2000 Si, 4000 O atoms) with the periodic boundary condition. We applied the Morse-Stretch potentials which describe the pairwise interactions between ions for SiO 2 system. There is structural phase transformation from tetrahedra (SiO4) to octahedra (SiO6) network structure. There is splitting in the Si-Si pair radial distribution function (PRDF) at high pressure (100 GPa). The original of this splitting relates to the edge- and face-sharing bonds. The new second peak of the O-O PRDF at the high pressure originates from oxygen atoms of the edge-sharing bonds. Thus, there is rearrangement of O atoms. O atoms have tendency to more order arrangement that leads to form some oxygen hcp and fcc structure in the model at high pressure. Keywords: Molecular Dynamics simulation (MD), Silica (SiO2), Structure, the peak splitting. 1. Introduction Silica (SiO2) is one of the most intensively investigated materials due to its importance in high technology materials (ceramic, semiconductor, solar cell) and geophysical sciences. SiO2 is typical network-forming oxide that studied for a long time by both experiments (X-ray diffraction, neutron diffraction, nuclear magnetic resonance, ) and simulations. These studies have shown that under different temperature and pressure conditions, the change of network structure have a great influence on the physical properties of the SiO2 material. Zachariasen [1] predicted that the structure .
