STRUCTURAL TRANSITION IN OXIDE SYSTEMS

Abstract

This paper presents the research results of the material microstructures of Al2O3, SiO2, using the method of molecular dynamics with the Born-Mayer interaction. Local structures of Al2O3, SiO2 and A2S under pressure are studied and analyzed through the radial distribution function, coordination number and distance bond length. The paper focuses on doing the research to clarify the change of the material microstructures of Al2O3, SiO2, in comparison with Al2O3.2(SiO2) (donated as A2S), with the purpose of demonstrating the nature and the existence of basic structure units: TO4, TO5, TO6 T is Si or Al) The research results showed that for the SiO2 systems, when the pressure increases, coordination number also increases, and microstructure change from SiO4 to SiO5. For Al2O3 systems, at low pressure mainly surrounded O are 4 Al atoms. When the pressure increases, this rate reduces; meanwhile, 5 Al atoms surrounding O increase very sharply. Besides, the dependence of refractive index on density will also be calculated and discussed in this paper.