Ab initio molecular dynamics study of diffusion mechanism in liquid B2O3 under pressure

Computer simulation based on molecular dynamics is powerful approach to clarify the microscopic mechanism of atomic diffusion in liquid state. Here, the diffusion properties and the microscopic diffusion mechanisms in liquid B2O3 under pressure are studied by ab initio molecular dynamics simulations. It is found that diffusivities of liquid B2O3 show anomalous pressure dependence. Diffusion coefficients of liquid materials usually decrease with pressure. However, that of liquid B2O3 increases with increasing pressure up to about 10 GPa. Additionally, diffusivity of boron becomes about twice larger than that of oxygen under pressure above 20 GPa. These anomalous pressure dependences are strong related to the microscopic atomic diffusion in liquid B2O3.