Molecular Dynamics and Laboratory Experiments on Diffusion in Liquid Oxides

9316390 Richter提出了在熔融SiO2和GeO2中扩散的详细研究。 结合分子动力学（MD）模拟和实验室实验的幅度，激活能，和激活体积的Si，O和Ge的自扩散将进行。 实验室实验将提供重要的基准，以测试MD模拟的有效性进行了使用各种表示的对电位。 目前使用的电位在再现液体SiO2的各种静态性质方面是相当成功的，但是它们还没有在再现动力学量（例如原子种类的扩散率）的能力方面进行测试。 验证一个简单的氧化物的MD模拟是一个必要的第一步，对硅酸盐熔体的现实表示，并将提供一个基础，在原子水平上理解扩散。 一个特别感兴趣的问题是，为什么所有最近的MD模拟的液体SiO2发现，自扩散的Si和O几乎是相同的，而实验室实验的混合氧化物系统总是发现它们是显着不同的？

9316390 Richter A detailed study of diffusion in molten SiO2 and GeO2 is proposed. Combined Molecular Dynamics (MD) simulations and laboratory experiments for the magnitude, activation energy, and activation volume for the self-diffusion of Si, O, and Ge will be carried out. The laboratory experiments will provide important benchmarks with which to test the validity of MD simulations carried out using a variety of representations of the pair-potentials. Presently used potentials are reasonably successful at reproducing various static properties of liquid SiO2, but they have not been tested in terms of their ability to reproduce kinetic quantities such as the diffusivity of atomic species. Validating the MD simulations for a simple oxides is a necessary first step towards the realistic representation of silicate melts, and will provide a basis for understanding diffusion at an atomistic level. A question of particular interest is why do all recent MD simulations of liquid SiO2 find that the self-diffusion of Si and O are virtually the same while laboratory experiments on mixed oxide systems always find them to be significantly different?