Postdoctoral Research Associateship: Computer Simulation ofDynamic Processes in Condensed Phase Systems

在分子动力学和蒙特卡罗模拟中，必须为数百万种构型反复计算多体系统的能量。因此，必须使用允许快速计算的理论和算法。在量子化学中，扩展的哈克方法是计算能量最经济的理论方法之一。虽然简单，但这种方法在适当选择的应用中给出了足够准确的结果。因此，分子动力学和蒙特卡罗模拟与扩展的Huckel方法的结合对于研究近表面和固态的动态现象是有用的。本研究将利用扩展的Huckel方法和蒙特卡罗模拟研究Si(111) (3 × 3) R30 -B表面结构的重建。密度泛函理论是理想的扩展系统和大分子。虽然计算量很大，但它往往能给出很好的结果，特别是对于自由电子系统。这个理论的核心是基态能量是电子密度的唯一函数。在密度泛函计算中不需要任何迭代。研究的第二个重点将是继续探索将密度泛函理论与计算机模拟相结合来研究凝聚相系统的动态过程。

In molecular dynamics and Monte Carlo simulations, the energy of a many-body system must be computed repeatedly for millions of configurations. It is therefore essential to use theories and algorithms that allow for fast calculations. In quantum chemistry, the extended Huckel method is one of the most economic theoretical approaches for calculating energies. Although simple, this method gives sufficiently accurate results in appropriately selected applications. A combination of molecular dynamics and Monte Carlo simulations with the extended Huckel method should therefore be useful in studying dynamic phenomena near surfaces and in the solid state. The proposed research will study the reconstruction of the Si(111) ( 3 x 3) R30 -B surface structure using the extended Huckel method and Monte Carlo simulation. Density functional theory is ideal for extended systems and large molecules. Although computationally intensive, it tends to give excellent results especially for free-electron systems. Central in this theory is that the ground state energy is a unique functional of the electron density. There is no need for any iteration in density functional calculations. The second focus of the research will be to continue explorations of the combination of density functional theory and computer simulation to study dynamic processes in condensed phase systems.