【作者】 王思胜；

【导师】 盛六四； 张允武；

【作者基本信息】 中国科学技术大学 ， 核技术及应用， 2007， 博士

【摘要】 本论文分为两大部分：第一部分是原子分子物理线站调试和一些分子的实验研究，第二部分是van der Waals团簇的实验和理论研究。第一部分：原子分子物理线站的调试和一些分子的实验研究在第一章中，概述了同步辐射光源的发展以及一些特点，并对同步辐射在各种研究领域的应用作了简要介绍。着重讨论了同步辐射真空紫外光在原子分子研究领域中的应用，详细讨论了光与物质相互作用的一些基本概念，包括绝热电离能、垂直电离能、超激发态、光电离截面、原子分子的Rydberg态及离解和预离解的定义及相关的背景知识。在本章中，还对目前同步辐射真空紫外原子分子研究中常见的几种实验方法如光电离质谱、荧光光谱、光吸收谱、光电子谱及符合技术作了较详细的描述。在第二章中，介绍了国家同步辐射实验室二期工程已建成的原子分子物理光束线及配套实验站的调试过程和结果。该光束线由具有两个包含角的高分辨球面光栅单色器、前置镜系统和后置聚焦系统组成。首先简要描述了该光束线光学准直的经过，具体介绍了各个光学元件的安装。安装完成后的光束线可以提供在7.5-124 eV能量范围内调谐的真空紫外光，给出了光束线的监测手段及零级光位置的确定，对三块光栅，进行了能量定标，并利用一些原子和分子的特征峰分别测试了各个光栅的分辨本领和重复精度，在光栅覆盖的能量范围内，光通量均在10¹²photons s^-1以上，并测出了样品处的光斑小于0.5×0.8mm²，总结了光束线的总体性能。另外，对原子分子物理实验站作了具体介绍，讨论了分子束的形成机理、飞行时间质谱仪的设计原理及多级光电离室的原理和结构，给出了该实验站仪器配备情况，并简要介绍了该实验站配套的数据采集方法。经光束线光谱定标和测试，结果表明光束线和实验站具有较好的性能。在第三章中，利用高通量的同步辐射光源和自制的多级光电离吸收池装置，测量了NO、CO、乙腈、丙烯腈、苯系物中的苯和甲苯的光吸收谱，给出了部分电子态的电离能，分析了其中的自电离Rydberg态结构和一些振动能级，对部分结构做了精确指认，经过分析和比较，我们所得的结果比较精确和可靠。其中部分结果是首次利用圆筒形多电极光电离吸收池实验装置获得的，这些结果可为基础研究提供数据，对应用基础研究和环境保护方面也有一定的意义。第二部分：van der Waals团簇的实验和理论研究在第一章中，介绍了团簇的定义、团簇研究的发展及团簇科学研究的现状，说明了团簇研究的重要性。给出了产生中性团簇和团簇离子的实验技术和方法。综述了研究团簇离子的几种典型的实验技术，如流动技术、静态气体技术、束技术、囚禁离子的实验技术。给出了团簇的结合能、缔合反应的熵值、分子间弱作用力的分类及幻数等团簇有关的一些基本知识。最后着重介绍了量化计算的各种理论方法，对计算过程中的基组选择、团簇计算中的基组重叠误差及结构优化和频率计算方面做了详细描述。具体介绍了自然键轨道分析、分子中原子理论和GAUSSIAN 2计算方法。在第二章中具体介绍了van der Waals团簇的实验和理论研究结果。它们包括：1．首次利用国家同步辐射实验室合肥光源的真空紫外同步辐射，使NO分子和Ar原子混合物的超声分子束发生光电离，测量了Ar，NO和异类团簇Ar·NO的光电离效率谱。在谱中，在与Ar原子的共振线对应的能量区域（11.5—12.0 eV）观察到一个强的类共振结构。这个结果表明：在异类团簇Ar·NO的内部，稀有气体Ar原子的激发能转移到与它接触的分子NO上，使分子NO发生电离。2．Rg·NO团簇是分子团簇研究的重要原型之一。在量子化学计算的不同理论水平和基组中，我们选择CCSD（T）理论水平和cc-PVDZ基组计算Rg·NO和Rg·NO⁺的稳定几何构型和振动频率。计算结果显示这种团簇呈歪斜的T型结构，Rg原子靠近NO分子中N原子的一侧，Rg-N-O的角度随Rg原子量的增加而增大。我们还利用G2方法计算了Rg·NO的电离能和Rg·NO⁺的离解能，其中电离能是首次获得的。并首次得出：随着Rg原子的极化率的增加，Rg·NO的电离能从He·NO的9.265eV线性降低到Kr·NO的9.132eV，而Rg·NO⁺的离解能从He·NO⁺的0.017eV线性增大到Kr·NO⁺的0.156eV。并首次利用优化出的几何结构对Ar·NO复合物做了分子中的原子（AIM）和自然键轨道（NBO）分析，从AIM分析得出了复合物间成键临界点，以及键间的电子密度和相应的拉普拉斯值，在NBO分析中，给出了重要轨道的电子占有数和轨道间电荷转移的关系和数量，并得到了二阶微扰稳定化能ΔE^（2）。3．在QCISD／cc-pVTZ水平上计算了Ar·CO和Ar·CO⁺的几何结构和相互作用能，首次利用分子中原子和自然键轨道理论分析Ar·CO和Ar·CO⁺复合物中具有键鞍点的原子间电荷密度和拉普拉斯值，得到了一些重要轨道的电子占有数、电子转移和轨道间二阶微扰稳定化相互作用能。利用QCISD／cc-pVTZ方法系统计算了Rg·CO和Rg·CO⁺的稳定几何构型和振动频率。并利用G2方法计算了Rg·CO复合物的结合能和电离能，以及计算了Rg·CO⁺复合物的离解能，其中电离能、部分结合能和部分离解能是首次获得的。从这些结果中我们得到了一些规律，理论结果和现有的实验结果符合的很好。不过，由于目前实验数据仍然很少，对这些基本的体系需要开展深入的实验研究。更多还原

【Abstract】 The dissertation includes two parts: The first part is the debugging of atomic and molecular physics beamline and endstation and the experimental study of some molecules. The second one is the experimental and theoretical study of van der Waals clusters.Part 1: Debugging of Atomic and Molecular Physics Beamline and Endstation and the Experimental Study of Some MoleculesIn the first chapter, a summary is given on the development and characteristics of synchrotron radiation. At the same time, a brief introduction is supplied about the application of synchrotron radiation in a variety of research fields. For the view of emphasis, it is reviewed that the application of synchrotron radiation in atomic and molecular physics with VUV light. The basic conceptions, including adiabatic ionization energy, vertical ionization energy, superexcited states, photoionization cross section, Rydberg state of atomic and molecular, dissociation and predissociation are discussed in detail. The common experimental methods, such as phoionization mass spectrometry, fluorescence spectrum, photoabsorption spectrum, photoelectron spectrum and coincidence technology are also introduced in this chapter.In the second chapter, an introduction is given about the debugging process and results of the atomic and molecular physics beamline and endstation of National Synchrotron Radiation Laboratory in the Phase II projects. The beamline consists of a spherical grating monochromator with two including angles, a pre-focusing mirror system and a post-focussing system. Firstly, a brief description is given on the optical alignment. A concrete introduction is given about the installation of every optical element. The beamline can provide the tunable VUV light in the energy range of 7.5-124eV. The methods of beamline’s detection and confirming the zero order’s position of gratings are given. For three gratings, energy calibration is done, and the energy resolving power and the reproducibility precision error is tested using the special peaks of some atoms and molecules. The photon flux is greater than 10 photons s^-1. The beam spot size at the sample is less than 0.5×0.8mm². In addition, the detailed introduction is given on the endstation of atomic and molecular physics. The formative mechanism of molecular beam is discussed. The theory of time of flight mass spectrometry and multi-photoionization chamber are also discussed in this chapter. Last, the method of data acquisition is described. By the spectra calibration of this beamline, the results indicate that this beamline and endstation have the good performances.In the third chapter, the photoabsorption of NO, CO, acetonitrile, acrylonitrile, benzene and toluene of benzene series have been measured by using a homemade experimental apparatus of cylindrical multi-stage ion chamber with high flux SR source. The ionization energies of some electron states are given. Their superexcited states, autoionization Rydberg states have been analyzed. By the analysis and comparison, our results are accurate and credibility. Some results are first obtained by using a cylindrical multi-stage ion chamber. These researches can supply the data for foundational study, and are of a definite importance for foundational study of application and the protection of atmosphere and entironment.Part 2: Experimental and Theoretical Study of van der Waals ClustersIn the first chapter, an introduction is given on the definition of cluster, the development of cluster research and the present status of cluster science. The experimental techniques and methods of neutral and ionic cluster are discussed. The review is given about the several typical technique of ionic complex, such as flow technique, static gas technique, beam technique and trap-ion technique. The foundational knowledge with respect to cluster is introduced, for example, bind energy, entropy value of associated reaction, classification of intermolecular weak interaction and magic number. Last, the introduction is done about the diversified method of theory. The detailed description is made for basis-set choice, basis-set superposition error, structural optimization and frequency calculation. These methods are specially introduced about the natural bond analysis, the atoms in molecules, GAUSSIAN-2.Some experimental and theoretical results of van der Waals clusters are given in the second chapter. They include:1. A supersonic beam of NO molecule mixed with Ar atom is ionized by VUV synchrotron radiation from Hefei Light Source（HLS） at National Synchrotron Radiation Laboratory （NSRL）. Photoionization efficiency spectroscopy （PIES） is first measured for NO, Ar and heterogeneous clusters NO·Ar. In PIES of NO·Ar, a strong resonance peak at the positions of the atomic rare gas resonance lines （11.5—12.0 eV） is observed, and it is shown that the excitation energy of the rare gas atom is transferred to the attached NO molecule within a heterogeneous cluster, leading to ionization of the molecule NO.2. Rg·NO cluster is one of the important prototypes for the study of molecular clusters. Among the different theoretical levels and basis sets of quantum chemistry calculation, the theoretical level CCSD（T） and the basis set cc-PVDZ is selected to calculate the equilibrium geometries and harmonic vibrational frequencies of Rg·NO and Rg·NO⁺（Rg=He, Ne, Ar and Kr）clusters. It is indicated that the geometry of Rg·NO cluster is a skewed T-shape, with the Rg atom located on the nitrogen side of the NO molecule, and the Rg—N—O bond angle augments with the increasing mass of Rg atoms. The ionization energies of Rg·NO and the dissociation energies of Rg·NO⁺ are calculated using G2 method. Some ionization energies are firstly obtained. We firstly found that with the increasing polarizability of the Rg atoms, the ionization energies decrease linearly from 9.265eV for He·NO to 9.132eV for Kr·NO, while the dissociation energies increase from 0.017eV for He·NO⁺ to 0.156eV for Kr·NO⁺ in linearly. The AIM and NBO analyses are also performed using the geometry from optimization. On the basis of the AIM topological analysis, we firstly get the bond critical points of complexes, the electron density of bond and the corresponding Laplacian value. According to the NBO analysis, occupation numbers of some important orbits, the charge transfer between orbits and second order perturbation energies are also obtained.3. The geometric structure and interaction energies of Ar·CO and Ar·CO⁺ complexes are calculated with cc-pVTZ basis set at QCISD level of theory. The electron density and Laplacian value at the bond critical point are first analyzed using the AIM and NBO theory. From these analyses, we can obtain the occupation numbers of some important orbits, charge transfer and second order perturbation energies between orbits. The geometric structure and vibrational frequencies of Rg·CO and Rg·CO⁺ complexes are calculated with QCISD/cc-pVTZ method. The bind energies and ionization energies of Rg·CO complexes and dissociation energies of Rg·CO⁺ complexes are calculated using the G2 method. Some ionization energies, dissociation energies and bind energies are first obtained. From the results, we deduce some rules. These theoretical results are in agreement with the ones of present experiments. However, because of the scare experimental datum presently, the farther experimental researches must be performed for these typical systems.更多还原