本文运用化学计算软件Gaussian03以及基于赝势和平面波基组的从头计算分子软件VASP， 研究了阴离子簇合物M⁻L[subscript n], (M⁻ = Na⁻, Li⁻,; L = H₂O, NH₃ ; n = 1-10) 中的电子结构和溶剂化作用。 / 文中选用基于密度泛函理论的B3LYP方法和6-311++G** 基组, 从Na⁻ 离子和Li⁻ 离子分别与不同溶剂分子 (H₂O和NH₃) 的相互作用入手，探讨以这类气态团簇化合物作为载体的体系中，溶解于其中的两个电子之间的相互作用以及电子与溶剂分子之间的相互作用。对于因溶剂分子极性的差异，导致形成不同形态的簇合物，进而影响了溶解于其中的电子对状态的研究，为实验上进一步探究被溶解的电子对提供了有利的理论依据。 / 在阴离子簇合物Li⁻(H₂O)[subscript n]中, 锂负离子和氧原子的强相互作用使得锂负离子被水分子包围。当n = 10，锂负离子的两个外层电子转移到水分子团簇中，并且电子对可以以单重态或三重态的电子态稳定存在。与之相反，在阴离子簇合物Na⁻(H₂O)n中，钠负离子的两个外层电子没有向溶剂中转移，钠负离子更倾向于与水分子团簇表面的氢原子相互作用而稳定在团簇表面。 / 在以氨分子为溶剂的阴离子簇合物Na⁻(NH₃)n和Li⁻(NH₃)n中, 金属负离子Na⁻ 和Li ⁻的两个外层电子随着溶剂分子的增加逐渐从金属离子上转移到溶剂 中。事实上，当n = 10时，簇合物Na⁻(NH₃)[subscript n]和Li⁻(NH₃)[subscript n]形成了两个溶解中心：被溶剂分子包围的金属阳离子，及其附近分散在溶剂分子中的电子对。这对电子可以以单重态或三重态的电子态稳定存在。与以水为溶剂的簇合物Na⁻(H₂O)[subscript n]和Li⁻(H₂O)[subscript n]不同的是，在Na⁻(NH₃)[subscript n]和Li⁻(NH₃)[subscript n]中，被溶解电子对更加弥散，广泛分布于溶剂分子中。 / The solvation and electronic structures in M⁻Ln₂, M⁻ = Li⁻ and Na⁻, L = H₂O and NH₃, and n = 1-10 were explored computationally by quantum chemistry calculation using Gaussian 03 package and by density functional theory based ab initio molecular dynamics simulation (AIMD) method with pseudopententials and a plane wave basis set using Vienna Ab Initio Simulation package (VASP). / Interactions of Na⁻ and Li⁻ anions in different solvent molecules, H₂O and NH₃, were calculated by B3LYP method with a basis set of 6-311++G** in order to explore the possibility that these clusters could serve as gas-phase molecule models for the solvation of two electrons. Such models would capture the electron-electron interaction in a solution environment. / For Li⁻(H₂O)[subscript n], the Li⁻ is buried in the water cluster due to the strong Li-O interaction, and by n = 10, the two loosely bound s electrons are indeed detached from lithium, and they could in either the singlet (spin-paring) or the triplet (spin-coupling) state. In contrast, for Na⁻(H₂O)[subscript n], the electron pair stays on the sodium, and the Na⁻ stays on the cluter surface, which is solvated by no more than 4 hydrogen atoms. The solvent-solvent interactions are favored as the water molecules from structures similar to observed in water anions. The formation of a solvated electron pair and the variation in solvation structures make these two cluster series interesting subjects for further experimental investingation. / With two s electrons, the Na⁻(NH₃)[subscript n] and Li⁻(NH₃)[subscript n] clusters are unique in that they capture the important aspect of the coupling between two solvated electrons. By first principles calculations, we demonstrate that the two electrons are detached from the metal by n = 10, which produces a cluster with a solvated electron pair in the vicinity of a solvated alkali cation, and the two electrons could also exist in both singlet and triplet state. They are quite distinct from the hydrated anionic clusters Na⁻(H₂O)[subscript n] and Li⁻(H₂O)[subscript n], in that the solvated electrons are delocalized and widely distributed among the solvent ammonia molecules. The Na⁻(NH₃)[subscript n] and Li⁻(NH₃)[subscript n] series therefore provide another interesting type of molecular model for the investigation of solvated electron pairs. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zhang, Han. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / TITLE PAGE --- p.I / ABSTRACT --- p.II / 论文摘要 --- p.IIV / ACKNOWLEDGEMENTS --- p.VI / CONTENTS --- p.VII / LIST OF TABLES --- p.X / LIST OF FIGURES --- p.XIII / Chapter Chapter One --- General Research Background / Chapter 1.1 --- General Introduction --- p.1 / Chapter 1.2 --- Electron in polar solvent --- p.1 / Chapter 1.2.1 --- Electron in water molecules --- p.1 / Chapter 1.2.2 --- Electron in ammonia molecules --- p.6 / Chapter 1.3 --- Experimental background of metal anion --- p.9 / Chapter 1.3.1 --- Li⁻(H₂O)[subscript n] and Na⁻(H₂O)[subscript n] --- p.9 / Chapter 1.3.2 --- Li⁻(NH₃)[subscript n] and Na⁻(NH₃)[subscript n] --- p.11 / Chapter 1.4 --- Scope of this thesis --- p.13 / Chapter 1.5 --- References --- p.14 / Chapter Chapter Two --- Theoretical Background / Chapter 2.1 --- Introduction --- p.18 / Chapter 2.2 --- The Schrödinger Equation and Born-Oppenheimer Approximation --- p.19 / Chapter 2.3 --- Hartree-Fock Theory --- p.20 / Chapter 2.4 --- Post-HF methods --- p.24 / Chapter 2.5 --- Density Functional Theory --- p.25 / Chapter 2.5.1 --- Kohn Sham (KS) scheme --- p.26 / Chapter 2.5.2 --- Local Density Approximation (LDA) --- p.29 / Chapter 2.5.3 --- Generalized Gradient Approximation (GGA) --- p.30 / Chapter 2.5.4 --- Hybrid Functionals --- p.30 / Chapter 2.6 --- DFT based ab initio Molecular Dynamics (AIMD) --- p.31 / Chapter 2.6.1 --- Plane Wave Basis Set --- p.34 / Chapter 2.6.2 --- Pseudopotentials and Projector Augmented Wave Method --- p.35 / Chapter 2.6.3 --- Molecular dynamics at constant temperature --- p.39 / Chapter 2.7 --- References --- p.40 / Chapter Chapter Three --- The identification of a solvated electron pair in the gaseous clusters of Na(H2O)n and Li(H2O)n / Chapter 3.1 --- Introduction --- p.42 / Chapter 3.2 --- Computaional methods --- p.45 / Chapter 3.3 --- Results and discussion --- p.46 / Chapter 3.3.1 --- Structure and energy for Na⁻(H₂O) and Li⁻(H₂O) --- p.46 / Chapter 3.3.2 --- H end structure for Na⁻(H₂O)[subscript n] --- p.52 / Chapter 3.3.3 --- O end structure for Li⁻(H₂O)[subscript n] --- p.58 / Chapter 3.3.4 --- Triplet structures for Li⁻(H₂O)[subscript n] --- p.64 / Chapter 3.3.5 --- Comparison between singlet and triplet Li⁻(H₂O)[subscript n] --- p.69 / Chapter 3.4 --- Conclusion --- p.73 / Chapter 3.5 --- References --- p.74 / Chapter Chapter Four --- The solvation of two electrons in the gaseous clusters of Na⁻(NH₃)n and Li⁻(NH₃)[subscript n] / Chapter 4.1 --- Introduction --- p.78 / Chapter 4.2 --- Computaional methods --- p.80 / Chapter 4.3 --- Results and discussion --- p.82 / Chapter 4.3.1 --- n = 1 --- p.82 / Chapter 4.3.2 --- H End Structures for Na⁻(NH₃)[subscript n] --- p.87 / Chapter 4.3.3 --- N End Structures for Li⁻(NH₃)n and Na⁻(NH₃)[subscript n] --- p.90 / Chapter 4.3.4 --- Triplet N End Structures for Li⁻(NH₃)[subscript n] --- p.97 / Chapter 4.3.5 --- Comparison between singlet and triplet Li⁻(NH₃)[subscript n] --- p.103 / Chapter 4.4 --- Conclusion --- p.105 / Chapter 4.5 --- References --- p.106
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_327979 |
| Date | January 2012 |
| Contributors | Zhang, Han, Chinese University of Hong Kong Graduate School. Division of Chemistry. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography |
| Format | electronic resource, electronic resource, remote, 1 online resource (xv, 109 leaves) : ill. (chiefly col.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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