Simulation of the structural state of amorphous phases in nanoscale SiO2 synthesized via different methods

Abstract

The structural state in nanoscaled SiO2 is probed experimentally via X-ray diffraction and the simulation method. The aerosil nanoparticles and nanoparticles synthesized via the electron beam evaporation are compared. The nanoparticles for all samples are shown to be in the amorphous state. The amorphous state of a SiO2 unit lattice is simulated via the molecular dynamics. The full-profile refinement of parameters for a simulated SiO2 phase (the Rietveld method) has allowed the complete structural information to be established at varying the specific surface. The unit cell parameters, the spatial atomic distribution and the degree of cell node occupation are determined, as well. The specific surface area is shown to decrease in aerosil nanoparticles and to increase in tarkosil nanoparticles with the increasing binding energy of atoms in a cell.