Monte Carlo simulations of ternary solid solutions of key petrological and technological importance.

该项目的重点是开发现实的活度-组成模型和计算多组分固溶体相的温度-压力-组成图，如铝硅酸盐和主晶石榴石、含Fe3+和K的绿辉石辉石和含Eu的粉状和碳酸盐。我们还将建立SiAlOns中Al/Si和N/O随温度变化的无序模型，这是一种具有有趣技术特性的新材料。这些模型将提高相平衡计算在变质岩和地幔岩石学、材料设计和长期核废料储存库安全预测等不同研究领域的准确性。为了完成这项任务，我们将开发一套专门用于三元固溶体的计算机模拟和热力学模拟的软件。该软件将建立在通用格子程序(GULP)和我们自己的蒙特卡罗代码之上，并将允许模拟具有一般对称性、大小和组成的超晶胞中可交换原子的玻尔兹曼分布。通过对蒙特卡罗结果进行热力学积分，可以得到固溶体相随温度变化的热力学混合性质。在执行这些任务的同时，我们将开发一个氧化物、氮化物、碳酸盐和钼酸盐的可转移经验原子间势数据库，与现有的数据库相比，其准确度更高。关键词：蒙特卡罗模拟，三元固溶体。

This project is focused on the development of realistic activity-composition models and the calculation of temperature-pressure-composition diagrams of multicomponent solid solution phases such as aluminosilicate and majoritic garnets, Fe3+- and K-bearing omphacitic pyroxenes and Eu-bearing powellites and carbonates. We will also develop models of temperature-dependent disorder of A1/Si and N/O in SiA1ONs - new materials with interesting technological properties. These models will permit to increase accuracy of phase equilibrium calculations in diverse research areas such as metamorphic and mantle petrology, materials design and safety prognosis of long-term nuclear waste repository. To accomplish this tasks we will develop a _exible suite of software dedicated for computer simulations and thermodynamic modelling of ternary solid solutions. The software will be build over the General Utility Lattice Program (GULP) and our own Monte Carlo code and will allow simulation of the Boltzmann distribution of exchangeable atoms in supercells of general symmetry, size and composition. Temperature-dependent thermodynamic mixing properties of solid solution phases will be obtained from the thermodynamic integration of the Monte Carlo results. In parallel with these tasks we will develop a database of transferable empirical interatomic potentials for oxides, nitrides, carbonates and molibdates with a superior accuracy compared to those currently available. Key words: Monte Carlo simulations, ternary solid solutions.