DFTB-based global optimization approach to large scale interfacial systems

该项目的目标是开发一种面向大规模界面系统结构确定的通用计算协议。这样的系统通常具有一定程度的复杂性，要求用全局优化技术确定无偏的几何形状。同时，内在目标是需要捕获量子效应的维度，因此需要电子结构方法来研究能量学。这两个限制加在一起，导致了目前很大程度上难以处理的计算成本。在这个项目中，我的目标是通过在更具成本效益的理论水平上引入几何预筛选来克服这一瓶颈，并建立一种专门针对具有未知成分和化学计量的界面系统的采样方法。对于后者，我将依赖于大规范采样技术，而对于前者，我将依赖于自一致电荷密度功能紧密结合（SCC-DFTB）。将为SCC-DFTB制定一致的参数化方案，使该方法可用于周期系统的所有元素。开发的协议将应用于各种各样的问题，共享广泛的结构筛选的必要性，即Si和RuO2表面重建的预测和氧化诱导的表面支持的TanOm团簇的再分散。

Aim of the project is the development of a versatile computational protocol geared towards the structure determination of large-scale interfacial systems. Such systems are generally of a level of complexity that dictates unbiased geometry determination with global optimization techniques. Simultaneously, intrinsically targeted are dimensions where quantum effects need to be captured and thus electronic structure methods are required for the energetics. Both constraints together lead presently to largely intractable computational costs. In this project I aim to overcome this bottleneck by introducing a geometric pre-screening at a more cost efficient level of theory and establishing a sampling approach specifically geared towards interfacial systems with often unknown composition and stoichiometry. For the latter I will rely on grand-canonical sampling techniques, while for the prior I will rely on Self-Consistent Charge Density Functional Tight Binding (SCC-DFTB). Specific efforts will be placed into a consistent parametrization scheme for SCC-DFTB that makes this approach available for all elements of the periodic systems. The developed protocol will be applied to diverse problems sharing the necessity for extensive structural screening, namely the prediction of Si and RuO2 surface reconstructions and the oxidation-induced redispersion of surface-supported TanOm clusters.