毕业论文移动版

摘要本文采用基于密度泛函理论（DFT）中的B3LYP方法和6-31G(d)基组对构建好的B5H9构型进行结构优化，得到能量最低构型。并研究基态结构的稳定性、磁性和光谱等性质。主要结论如下：

1、稳定性分析表明，B5H9热稳定性较高，化学稳定性较低；86399

2、NBO分析B5H9基态结构的电荷布局特性和部分成键性质，发现其电荷转移即s、p轨道杂化不仅发生在B原子内部，而其B、H原子之间也有杂化现象；

3、红外光谱分析表明B5H9的振动范围分布在600-2800cm-1处，振动强度主要分布在200-700km·mol-1处；

4、电子性质和磁学性质研究表明，B5H9总磁矩较小，B原子对总磁矩贡献比H原子要大。

5、B5H9芳香性计算结果表明在中心(0。100nm)处的NICS值受键的局域顺磁的影响最小；芳香性随垂直距离的改变而改变，同时也表明在B5H9中具有多重芳香性。

毕业论文关键词：B5H9；稳定性；光谱性质；电磁性质；芳香性；密度泛函理论

Abstract  In this paper, based on B3LYP and 6-31G(d) in density functional theory to optimize the structure and calculate the frequency after the B5H9 model has been constructed。And studied the stability of the ground state structure, magnetic and optical properties,main conclusions are as follows:

(1)Stability analysis show that B5H9 has the high thermal stability, and the low chemical stability。

(2)NBO analysis B5H9 part charge layout characteristics of the ground state structure and bonding properties, found that the charge transfer namely, s, p orbital hybridization occurs not only inside the B atoms, and there is also a hybrid phenomenon between the B and H atoms。

(3)The vibration of the infrared spectrum analysis showed that B5H9 range in 600-2800cm - 1, vibration intensity are mainly distributed in 200-700 km · mol - 1。

(4)Electronic properties and magnetic properties research shows that B5H9 total magnetic moment is small,B atoms contribution to total magnetic moment is bigger than the H atoms

(5)B5H9 aromaticity calculation results show that the NICS (0。100 nm) at the center value is affected by key LAN paramagnetic minimum; Aromaticity change with the change of the vertical distance and, at the same time also shows that has multiple in B5H9 aromaticity。

Keywors:B5H9,tability,optical properties,electromagnetic properties, aromaticity; 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 研究对象 1

1。1。3 研究意义 2

1。2硼氢团簇的研究和意义 2

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） 5

2。2。1 DFT简介 5

2。2。2 DFT应用 5

第三章 B5H9的结构和性能 7

3。1 引言 7

3。2 计算方法 7

3。3 结果与讨论 8

3。3。1几何构型 8

3。3。2结构稳定性 9

3。3。3自然键轨道（NBO） 10