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 ${\mathrm{SiO}}_2$.

• Received 17 September 2003

DOI:https://doi.org/10.1103/PhysRevB.70.134204