摘要采用Material Studio5。5中的Dmol3模块，在GGA-PW91交换关联梯度泛函的基础上对WnCu(n=1-7)团簇进行几何结构全优化，得到了WnCu(n=1-7)团簇的基态构型，并研究了基态结构的稳定性、磁性和光谱等性质。主要结论如下：86315

1、WnCu(n=1-7)团簇基态结构的多重度普遍较低。WCu团簇的基态结构为线性结构，W2Cu的基态结构为平面结构，WnCu(n≥3时)基态结构均为立体结构；W4Cu和W5Cu团簇的基态为半封闭的构型，其他基态均为封闭的结构；

2、稳定性分析表明，WnCu(n=1-7)团簇的平均结合能随着团簇尺寸的增加而逐渐增大，二阶能量差分、能隙均出现了明显的“奇-偶”振荡。W2Cu、W4Cu、W6Cu团簇的热力学稳定性较高，化学稳定性较低；

3、电子性质和磁学性质研究表明，当n≥2时，局域态密度(PDOS)和总态密度(TDOS)在图中横轴的上下部分曲线对称性高，总磁矩较小；

4、红外光谱分析表明，W2Cu团簇和W5Cu团簇的红外光谱的振动强度相对较强，振动范围大都分布在100-300cm-1处，振动强度主要分布在0-6km·mol-1。

毕业论文关键词：钨铜团簇；结构和稳定性；磁性和电子性质；红外光谱；密度泛函理论

AbstractThe structures and properties of WnCu(n=1-7) clusters are systematically investigated by density functional theory (DFT) in the theoretical frame of the generalised

gradient approximation (GGA) exchange-correlation functional at the PW91 level。And the main conclusions are as follows:

1。The spin multiplicity of WnCu（n=1-7）clusters is generally low。The ground state of WCu cluster is linear,however,from the n=2 to the n=3 the ground state structures is transformed from 2D to 3D。 And the ground state structures of W4Cu and W5Cu are semi-closed while the others are closed。

2。The research on stability shows that the average binding energy increases as the cluster sizes fill out。Even-odd oscillation appears in the results of ∆2E and Eg。W2Cu，W4Cu and W6Cu clusters were more thermodynamically stable than the others but their chemistry stability were low。 

3。Through the analysis of electronic properties and magnetic properties,PDOS and TDOS balance well when the n≥2 so that the magnetic properties of clusters are small。

4。Through the infrared spectrum analysis of the ground state,the vibration intensity of peak of W2Cu and W5Cu clusters is relatively larger。The vibration rate ranges from 100 to 300 cm-1 and the intensity ranges from 0 to 6 km·mol-1。

Keywords:tungsten copper clusters;structure and stability;magnetic and electronic properties;infrared spectral;Density Functional Theory

目  录

第一章 绪论 1

1。1 团簇物理简介 1

1。1。1 团簇概念 1

1。1。2 团簇的主要性质 1

1。2 钨基团簇及铜基团簇的研究进展 2

1。2。1 过渡金属团簇的研究 2

1。2。2 钨基团簇的研究 2

1。2。3 铜基团簇的研究 3

1。3 主要研究内容 3

第二章 理论基础 4

2。1 量子化学 4

2。2 密度泛函理论(DFT) 4

2。2。1 局域密度近似泛函(Local Density Approximations, LDA) 5

2。2。2 广义梯度近似泛函(Generalized Gradient Approximation，GGA)