贵金属纳米簇合物微观结构与光电子能谱的理论研究

This project focuses on the microscopic structure and photoelectron spectroscopy of noble metal nanoclusters (NMNCs). From the point of view of atomic and molecular physics,we hope to establish a theoretical model for the structure optimization of noble metal nanoclusters, and then develop a theoretical method which can describe the electroic and magnetic structure for noble metal nanoclusters. Photoelectron spectroscopy experiments combined with theoretical calculation can obtain the electronic structure of size controllable cluster anions, which provide a benchmark for solving the problem that the neutral nanometer metal clusters are difficult to be obtained in the present experiment in the study of the geometric and electronic structures; the special properties of materials are detected and predicted by changing electronic structure and magnetic properties of the system on the basis of chemical adsorption or doping artificially. The aim of the present project is to discover the basic structural unit, bonding rules and microcosmic mechanism of noble metal nanoclusters at the atomic and molecular levels,to develop a theoretical method for the lowest energy structure optimization on this systems, it also raise the cognitive ability on the variety of microscopic structure of noble metal nanoclusters along with cluster size. Therefore, the physical problem about microstructure and photoelectron spectroscopy of noble metal nanoclusters is of great significance for the promotion in cross-development of the atomic and molecular physics and cluster physics.

以贵金属纳米簇合物(Noble metal nanoclusters,NMNCs)的微观结构与光电子能谱为研究目标，从原子与分子物理学的角度出发，建立一种对贵金属纳米簇合物体系进行快速全局优化的理论模型，发展一种能描述贵金属纳米簇合物电磁结构的理论方法。通过光电子能谱测量与理论计算相结合的方法获得尺寸可控阴性纳米团簇体系的电子结构，为解决目前中性纳米金属簇合物在实验研究中难以获得精确的几何和电子结构等微观信息提供依据；采用化学吸附或掺杂人为改变体系的电子结构、磁性等性质，发现和预测特殊材料的奇异性质。本项目的目标是在原子和分子水平上探讨贵金属纳米簇合物的基本结构单元、成键规则和微观作用机理，发展一种能对该体系进行全局优化的理论方法，并从微观机理上提升人们对贵金属纳米簇合物微观结构随尺寸变化的认知能力；因此，这一物理问题的解决对于促进原子与分子物理与团簇物理的交叉发展有非常重要的意义。

本项目对过渡金属掺杂组成的贵金属纳米簇合物微观结构与光电子能谱展开了理论研究。主要工作进展包括以下几个方面：(1)在团簇异构体结构优化中采用随机搜寻踢球模型与密度泛函理论模型相结合的方法完成金基二元团簇的结构优化。(2)通过不同的过渡金属原子的掺杂可以改变原来纯金纳米团簇的电子几何结构与磁性等性质，发现金基二元团簇具有反常的物理化学性质。(3)通过光电子能谱测量与第一性原理计算相结合的方法可以获得尺寸可控阴性纳米金基二元团簇体系的几何结构，为解决目前纳米金属簇合物在实验研究中难以获得精确的几何和电子结构等微观信息提供了理论依据。研究发现Sc@Au16– 团簇具有很高的平均结合能与掺杂能，反衬出该团簇的极大的稳定性。(4)在磁性方面重点探讨了3d掺杂原子对总磁矩的贡献，Mn、Cr原子的磁性存在着减弱的现象。