氟利昂在外场作用下的光谱研究

氟利昂在外场作用下的光谱研究(论文15000字)
摘要：氟利昂是破坏大气臭氧层的元凶。本文利用激光质谱实验技术结合高精度理论计算方法研究了几种典型氟利昂分子（氟利昂F12B1、氟利昂F1110、氟利昂F31和氟利昂F114B2）在外场（包括电场和激光场）作用下的光谱和物理特性。首先利用激光质谱技术得到F1110和F114B2在飞秒激光作用下的飞行时间质谱图，通过分析得到解离通道。然后采用密度泛函理论的B3LYP方法，在6-311G++(d,p)基组水平上对F12B1、F31和F114B2分子以及F1110离子在不同电场下的结构进行优化。并在此基础上计算振动频率，分析其红外光谱和拉曼光谱随电场的变化趋势。另外，通过利用CIS/6-311G++(d,p)计算这些分子和离子的激发态能量，研究了电场对紫外可见吸收光谱的影响。而且，在同样的基组下通过对F31分子的C-Cl键进行势能扫描,发现随电场的增大，解离势能的势垒逐渐降低。当F=0.04a.u.时势垒已经消失，F31分子因C-Cl键断裂而降解。这些实验和理论结果为外场降解污染物和保护臭氧层提供重要的参考依据。
关键词：光谱学；氟利昂；激光质谱；外电场；降解
 
Study on spectra of Freon under the external fields
Abstract:Freon is the prime culprit of destructing the atmospheric ozone layer. The physical and spectral characteristics of some typical Freon(F12B1, F1110, F31 and F114B2) under external fields(electric fields and laser fields) are investigated which combine laser mass spectrometry experimental technology with high-level calculation method. Firstly, Time-of-flight mass spectra of F1110 and F114B2 under action of a femtosecond laser pulse are obtained by time-of-flight mass spectrometry technology. The channels of dissociation are analyzed through mass spectra. The molecular structures of F12B1, F31 and F114B2 and the ionic structure of F1110 are optimized using the density function theory (B3LYP/6-311++G(d, p)). The vibrational frequencies are calculated on this basis. And the effects of external fields on the infrared spectra and the Raman spectra of these Freon are studied. Additionally, the UV-VISabsorption spectra of these molecules and ion under different electric fields are investigated through calculating energy with CIS method. Besides, the potential energy surface of F31 about C-Cl bond is scanned at the same basis set. The result indicates the barrier of dissociation gradually decreases with the increase of electric fields. The barrier has disappeared under electric field of 0.04a.u., and the molecule induces to degradation because of C-Cl bond breaking. The experimental and computed results offer important reference for degradation and protecting atmospheric ozone layer.
Keywords: spectroscopy;Freon; laser mass spectrometry; electric field; degradation
 

目录
摘要    IV
Abstract    V
1 绪论    1
1.1 氟利昂与臭氧层的破坏    1
1.2 外场对分子性质的影响    1
1.3 本文的研究内容和研究意义    2
2 理论方法与实验装置    3
2.1实验技术和装置    3
2.2 理论方法    4
3 氟利昂F12B1在电场作用下的光谱研究    5
3.1 F12B1分子的稳定构型    5
3.2 电场对F12B1分子红外和拉曼光谱的影响    5
3.3 电场对F12B1分子紫外可见吸收光谱的影响    8
3.4 电场对分子轨道能级和能隙的影响    10
4 氟利昂F1110在激光场和电场作用下的光谱研究    11
4.1 F1110在飞秒激光场作用下的动力学研究    11
4.2 可见光与红外光辐射下质谱图的比较    12
4.3 C2Cl4+在电场作用下的光谱研究    13
5 强电场对氟利昂F31的光谱和降解研究    15
5.1 F31的稳定构型    15
5.2电场对F31分子的红外光谱影响    16
5.3 电场对紫外可见吸收光谱的影响    18
5.4电场对分子解离的影响    18
6氟利昂F114B2在激光场和电场作用下的光谱研究    19
6.1 F114B2在飞秒激光场的动力学研究    19
6.2 电场对F114B2分子紫外可见吸收光谱的影响    20
7结论    21
参考文献    22
致谢    26