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功能纳米材料结构—性质关系的理论研究

作　者: 孙进
导　师: 梁万珍
学　校: 中国科学技术大学
专　业: 化学物理
关键词: 单壁碳纳米管吸收光谱光谱性质振动结构理论研究发射光谱富勒烯电子结构强激光场低聚物
分类号: TB383.1
类　型: 博士论文
年　份: 2008年
下　载: 209次
引　用: 0次
阅　读: 论文下载

内容摘要

In my thesis, I present the major works that I have finished during my PhD study. In the past 4-5 years, my research is focused on developing and applying the time-dependent density functional theory (TDDFT) or time-dependent Hartree-Fock (TDHF) theory or novel numerical algorithms to investigate the electronic structures, optical spectra and ultrafast electron dynamics of nano-size functional materials. We perform theoretical studies toward understanding the interaction between the materials and the external fields, the principles of linear and nonlinear responses of the materials, the mechanism of the molecular high-order harmonic generation, the nonadiabatic effect of polyatomic molecules in the intense laser field and the coupling effect of electron—nuclei of flexible conjugated polymers, etc. The following three manifolds are concerned: (1) We develop the time-dependent density functional theory and numerical algorithms to describe the interaction between the complex systems and intense laser fields, to investigate the electron dynamics of systems and to describe the coupling of electron-nuclei in complex molecular systems, (2) We study the mechanism of molecular high order harmonic generation theoretically and investigate the interaction between the harmonic spectra and polarization direction of the external field or the geometries of molecules to show the relationship between the geometries and electron structures which can not be observed in experiment. (3) We investigate the properties of some important systems, such as high order harmonic spectra of finite length C/BN nanotubes; the absorption and emission spectra of flexible conjugated polymers; the electron dynamics of polyatomic molecules using theoretical model and software about calculation of quantum chemistry. We consider the effect of sizes and geometries of nano-materials on electronic structures and dynamics and show the relationship between the geometries of functional materials and properties which can not be described in experiment easily.The main results are summarized as follows: 1. We develop fast propagator approaches to solve the time-dependent Kohn-Sham equation in TDDFT to investigate the electron dynamics of complex molecules, to describe the rearrangement of electrons and the ultrafast electron dynamics of molecules.2. By combining TDDFT and correlation equations, we construct a theoretical model and codes which can deal with harmonic and anharmonic oscillators and study the absorption and emission spectra of flexible conjugated polymers and the distribution of exciton.3. The calculations of silicon nano-clusters prove that, the silicon particles with sizes of 1nm and the optical excitations at 3.7, 4.0 and 4.66V observed in experiment may consist of 29 Si atoms surrounded by 24 hydrogen atoms not by 36 hydrogen atoms.4. The investigations about quasi-one-dimensional all carbon-nano-materials such as carbon nanotubes or polymers, show that, the geometries and sizes of the systems play a vital role on their physical properties such as energy bands and linear absorption spectra. And different systems require quite different system sizes to achieve the converged physical properties. Besides, doping also can alter the charge distributions, local electronic structures and linear optical feature.5. From the time-dependent simulations about systems in intense external field, we find when systems interact with strong laser field, C and BN nanotubes can generate high order harmonic very efficiently. So they are the ideal pulsed sources of the very fashionable atttosecond lasers. There are clearly differences of nonlinear optical properties between the finite and infinite size nanotube models. The laser can drive the electrons to move along or normal to the tubes being dependent on the polarization of field.6. The studies about polyfluorenes show that, the vibronic structure in absorption and emission spectra dependent on the chain geometries and temperature very distinctly. And chemical substitudents have appreciable influence on both absorption and emission spectra. Besides, for fluorescence proteins, the optical properties can decides by their chromophore mainly, but protein environment also have influence.

全文目录

Abstract  5-7
攻读学位期间的论文发表情况  7-12
第1章绪论  12-18
  参考文献  17-18
第2章基本理论知识  18-40
  2.1 静态的密度泛函理论  18-20
    2.1.1 Hohenberg-Kohn理论  18
    2.1.2 Kohn-Sham方程:有效单电子近似  18-20
  2.2 含时密度泛函理论  20-25
    2.2.1 含时Kohn-Sham方程的推导  20-25
  2.3 含时响应理论  25-28
  2.4 在时间域里传播约化单电子密度矩阵  28-32
    2.4.1 Runge-Kutta方法  29-30
    2.4.2 Magnus积分方法  30-32
    2.4.3 Krylov子空间方法  32
  2.5 局域密度矩阵方法  32-37
    2.5.1 线性标度方法的重要性  32-33
    2.5.2 用TDHF描述一个闭壳层体系  33-34
    2.5.3 在TDHF框架下的局域密度矩阵方法  34-37
  参考文献  37-40
第3章对纳米团簇分子体系光谱性质的理论研究  40-51
  3.1 计算方法与测试  40-44
    3.1.1 对于光谱的计算方法  40-41
    3.1.2 对于各种传播子方法的测试  41-44
    3.1.3 小结  44
  3.2 对于硅纳米团簇光谱性质的研究  44-49
    3.2.1 研究背景  44-45
    3.2.2 硅纳米团簇的吸收光谱  45-47
    3.2.3 小结  47-49
  参考文献  49-51
第4章对于纳米材料体系线性吸收光谱性质及电子结构的理论研究  51-73
  4.1 关于富勒烯及碳纳米管简介  51-54
    4.1.1 富勒烯和富勒烯聚合物  51-52
    4.1.2 碳纳米管的发现和研究进展  52-54
  4.2 对C_(60)聚合物、碳纳米管的电子结构及吸收光谱的理论研究  54-63
    4.2.1 研究背景  54
    4.2.2 计算方法  54-55
    4.2.3 计算结果  55-62
    4.2.4 小结  62-63
  4.3 通过在碳纳米管中封装不同分子来控制掺杂的理论研究  63-69
    4.3.1 研究背景  63
    4.3.2 分子体系的选择  63-64
    4.3.3 固体性质的计算  64-66
    4.3.4 光学性质的计算  66-68
    4.3.5 小结  68-69
  参考文献  69-73
第5章对于碳纳米管和硼氮纳米管在强激光场中非线性谐波光谱和动力学性质的理论研究  73-98
  5.1 硼氮纳米管简介  73-74
  5.2 预备工作  74-77
    5.2.1 强激光场中高阶谐波的产生机理  74
    5.2.2 谐波的计算方法  74-75
    5.2.3 对于苯分子的测试  75-77
  5.3 对有限长碳纳米管谐波光谱的理论研究  77-85
    5.3.1 研究背景  77-78
    5.3.2 计算结果  78-83
    5.3.3 小结  83-85
  5.4 硼氮纳米管在强激光场中多电子动力学过程的理论研究  85-94
    5.4.1 研究背景  85-86
    5.4.2 计算结果  86-92
    5.4.3 小结  92-94
  参考文献  94-98
第6章带有振动结构的吸收和发射光谱  98-128
  6.1 对于荧光聚合物电子激发态的理论研究  98-115
    6.1.1 研究背景  98-99
    6.1.2 理论模型  99-103
    6.1.3 计算结果和讨论  103-114
    6.1.4 小结  114-115
  6.2 对于荧光蛋白质荧光态性质的理论研究  115-123
    6.2.1 研究背景  115-116
    6.2.2 计算结果  116-121
    6.2.3 小结  121-123
  参考文献  123-128
致谢  128

功能纳米材料结构—性质关系的理论研究

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