Development of the simulation system for predicting structural and physical properties of minerals

能量最小化、晶格动力学和分子动力学这三种模拟方法经常被用来计算在较宽的温度和压力范围内矿物的结构和物理性质。在这个项目中，我们为普通矿物学家准备了方便地使用这三种方法的计算机程序。我们通过经验和非经验两种方法进一步发展了用于含Na、Mg、Al、Si、K、Ca和O离子的地球材料的精确的原子间势。在经验方法中，离子间势被认为是晶体中两两相加的库仑、范德华和排斥相互作用以及多体相互作用的总和。呼吸壳模型被用来模拟多体作用力，其中离子的排斥半径在晶体中其他离子的作用下各向同性地变形。在非经验方法中，采用从头算Hartree-Foxk自洽场计算方法，对由镁、硅、氧离子组成的模型团簇进行从头算Hartree-Foxk自洽场计算，并由计算得到的模型团簇的势能面计算出有效的原子间势。用第一性原理路径积分分子动力学方法模拟了热物性。

Three simulation methods, energy minimization, lattice dynamics, and molecular dynamics techniques, are often used to calculate structural and physical properties of minerals over wide temperature and pressure ranges. In this project, we prepared for general mineralogists to easily use the computer programs for the three methods. We further developed accurate interatomic potentials for use in computer simulation of Earth materials containing Na, Mg, Al, Si, K, Ca, and O ions by both empirical and non-empirical techniques.In the empirical technique, the interionic potentials are taken to be the sum of pairwise additive Coulomb, van der Waals, and repulsive interactions, and many-body interactions in crystals. The breathing shell model is used to simulate the many-body forces, in which the repulsive radii of ions are allowed to deform isotropically under the effects of other ions in the crystal. Energy parameters were derived to accurately reproduce the observed structures, the measured thermal and elastic properties of rock-forming minerals including silicas, feldspars, pyroxenes and their polymorphs, olivines and their polymorphs, and some oxides.In the non-empirical method, ab initio Hartree-Foxk self-consistent-field calculations were applied to model clusters composed of Mg, Si, and O ions, and effective interatomic potentials were obtained from the calculated potential energy surfaces of the model clusters. The first-principles path-integral molecular dynamics method is also used to simulate thermal properties.