A First-Principles Computational Framework for Liquid Mineral Systems

摘要

Computer modeling of liquid phase poses tremendous challenge: It requires a relatively large simulation size, long simulation time and accurate interatomic interaction and as such, it produces massive amounts of data. Recent advances in hardware and software have made it possible to accurately simulate the liquid phase. This paper reports the details of methodology used in the context of liquid simulations and subsequent analysis of the output data. For illustration purpose, we consider the results for the liquid phases of two geophysically relevant materials, namely MgO and MgSiO_3. The simulations are performed using the parallel first-principles molecular dynamics (FPMD) technique within the framework of density functional theory. Various physical properties including the equation of state, diffusion, atomic structure and electronic structure of these liquids are obtained as a function of pressure and temperature. The three-dimensional and time-dependent data for atomic configuration and electronic density are analyzed using the recently developed space-time-multiresolution and multiple-dataset-visualization techniques. It is shown that the structural, dynamical and electronic properties of the liquid phases are highly sensitive to compression, with no discernible influence of temperature in most cases.