Molecular dynamics study on structure and properties of liquid and amorphousAl2O3

Abstract

Structure and thermodynamics properties of liquid and amorphous ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ have been investigated by Static Relaxation (SR) and Molecular Dynamics (MD) methods. Simulations were done in the basic cube under periodic boundary conditions containing 3000 ions with Born-Mayer type pair potentials. Structure of liquid and amorphous ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ models is in good agreement with experiment. The microstructure of ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ system has been analyzed through pair radial distribution functions, coordination number distributions, interatomic distances or pore distribution (for amorphous state only). Temperature dependence of the pore distribution in amorphous ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ was obtained. A thermal expansion coefficient and self-diffusion constants have been calculated. The temperature dependence of diffusion constants D in liquid ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ shows an Arrhenius law with activation energies which are close to experimental ones for liquid ${\mathrm{SiO}}_{2}$.