锕系纳米团簇的电子结构及性质的理论研究

With the rapid development of computer technology and artificial intelligence research, the theoretical chemistry and computational simulation of actinides are very important for the development of nuclear chemistry and radiochemistry, and have become an indispensable and important tool. In solution, the actinide ions are present in the form of complex ions and nanoclusters. Therefore, research on actinide nanoclusters will be critical to future environmental issues. This project intends to use the density functional theory and wave function theory method to carry out quantum chemical theory calculation and analysis on the actinide nanoclusters. First, high-precision coupled cluster method is applied to the small actinide complexes, of which the data can be compared with results from various density functional calculations in order to figure out the most accurate density functional for actinide nanoclusters. Second, the corresponding density functional as well as DLPNO-CCSD(T) computational simulation will be carried out for the actinide nanoclusters to investigate the geometry structures, electronic structures and spectral properties. The goal is to deepen the understanding of the clustering mechanism for the actinide nanoclusters, to explore the essential basis and physical foundations for the stability of these nanoclusters, and to find out the correlation rule between the ions & pH values in solution and the clustering mechanism as well as the stabilization of the actinide nanoclusters. The research program will provide the theoretical basis for the effective treatment of groundwater and nuclear waste containing actinide radioactive pollutants.

随着计算机技术和人工智能研究的飞速发展，锕系理论化学和计算模拟对于核化学与放射化学的发展十分重要，已经成为不可或缺的重要工具。在溶液中，锕系离子以配合物离子和纳米团簇的形式存在。因此，对錒系纳米团簇的研究将对未来的环境问题至关重要。本项目拟采用密度泛函理论和波函数理论方法两大类方法对锕系纳米团簇进行量子化学理论计算模拟分析。首先高精度耦合簇方法计算结构和已发表的实验结果对小的錒系纳米簇合物根据进行各种密度泛函进行计算评估，然后使用准确的高精度泛函对各种錒系纳米团簇几何结构、电子结构和光谱性质开展系统的计算模拟研究。目标是增加对锕系纳米团簇成簇机理的理解，探索錒系纳米团簇稳定性的理论基础和物理原因，总结溶液中离子浓度和pH值大小对錒系纳米团簇成簇机理和稳定性大小的影响规律，为有效处理含有錒系元素放射性污染物的地下水及核废料处理提供有效的理论依据。

锕系元素尤其是前锕系元素因其相对弥散的5f, 6d和7s轨道，使其类似于前过渡金属元素，容易形成高价氧化态多酸类团簇结构。申请人以铀酰团簇U60与富勒烯碳团簇C60的拓扑结构相似性为出发点，通过采用最新开发的锕系赝势和基组，从理论上预测了类石墨烯二维铀酰材料具有动力学和热力学稳定性。理论研究表明在类石墨烯二维铀酰材料中存在着由超氧 (O₂-) 2p 轨道构成的一维反铁磁海森堡链。该一维反铁磁海森堡链的稳定机制可以通过 2pπ*–5fδ–2pπ*超交换作用模型加以解释。该研究推动了反铁磁电子器件材料的潜在应用。该研究将类石墨烯二维材料的设计由s-区、d-区元素拓展到了f-区锕系元素，丰富了锕系团簇及其展开的二维材料的研究领域。