新一代通用密度泛函方法开发和测评

密度泛函方法已经成为实验科学不可或缺的有益补充。然而越来越多的证据显示，目前主流密度泛函方法在现有的理论框架下存在着一些不可逾越的挑战：1）无法达到实验科学要求的化学精度——1kcal/mol；2）无法同时描述好有限分子和无限固体的电子行为；3）无法同时兼顾强、弱关联相互作用的描述。本项目书中，申请人拟结合固体物理和量子化学领域泛函方法开发的成功经验，挖掘在泛函近似中引入未占轨道信息的巨大潜力，开发新一代通用密度泛函方法。申请人还拟搭建可同时高效地处理有限分子簇模型和周期性边界条件模型的新一代通用泛函程序包，以及可用于准确评估新方法在应对上述三个挑战的测试平台。本工作有望进一步提升密度泛函方法的准确度和普适性，使之能够发挥指导实验和设计实验的基础性作用。

Density functional theory (DFT) has been an indispensable complement to the experimental science. However, there is growing evidence, showing that commonly used density functional approximations (DFAs) 1) are not competent of providing the prediction accuracy of 1 kcal/mol desired in experiment; 2) fail to capture the electronic behavior in both the environment of finite cluster model and periodic boundary conditions; 3) cannot describe strong and weak correlation simultaneously well. In this proposal, the applicant attempts to coalesce the successful experience in condensed-matter physics and quantum chemistry for the method development, explore the potentiality and the strategy of using unoccupied orbital information in the functional construction and develop new-generation orbital-dependent DFAs for general-purpose use. The applicant will implement a software package for the newly developed DFAs, which features a massive parallel efficiency and the capability of simulating both molecular systems and condensed matter systems. A representative database will be established to provide a comprehensive benchmark for the three challenges aforementioned. This work aims at consistently improving the accuracy and universality of DFT methods, making them applicable to explain the complex experiments and even for rational experimental design.