CFCl3分子2e和4a1轨道的电子动量谱研究

由于工业的迅速发展,使得空气质量急剧下降,因此对影响大气的分子进行深入研究变得非常必要．本实验室已经对影响环境的甲烷[1]、丙烷[2]、CO2[3]等分子进行了电子动量谱研究,为环保提供了有用的数据．CFCl3作为工业广泛应用的气雾剂和制冷剂原料,它的大量使用导致了大气中臭氧的减少[4]．前人已用光电子谱学的方法[5-8]研究了CFCl3,我们又用电子动量谱的手段对CFCl3分子进行了进一步的研究,即从波函数的层次上详细了解CFCl3的电子结构．     

[C(AuPH3)m]n+ (m=4-6; n=0-2)成键性质和稳定性研究

用MP2/LanL2DZ方法优化C(AuPH3)4[1a(C4v); 1b(Td)], [C(AuPH3)5]+[2a(C3h); 2b(Cs)]以及[C(AuPH3)6}]2+[3a(C2h); 3b(C2v)]的结构, 得到的几何参数与实验值相符. MP2水平下的自然键轨道(Natural bond orbitals, NBO)分析表明, Au具有d(sp)杂化性质, 其中(sp)具有s-p混合的轨道性质; 沿C-Au辐射方向形成的σ键和切向Au-Au之间的弱吸引相互作用使得整个分子稳定. 化合物1a, 2和3具有2或3个二电子三中心键, 表明该类化合物具有与传统C化学不同的电子结构和立体化学构型.     

二氟甲烷分子3a1和2b2轨道的电子动量谱

The electron momentum spectroscopy of the inner valence orbitals 3a1 and 2b2 of methylene fluoride was studied by electron momentum spectroscopy（EMS）. The experiment was performed using a high resolution（ΔE=1.15 eV FWHM,Δp=0. 1 a. u.）（e,2e）EMS spectrometer. The experimental momentum profiles of these two orbitals are compared with those calculated by Hartree-Fork method and Density Functional Theory.     

烷烃客体分子(C_nH_m,n≤6,m≤14)在5~(12)6~2和5~(12)6~4水笼中的稳定性与拉曼光谱的密度泛函理论计算

可燃冰矿藏中气体成分非常复杂,通过谱学分析对水合物样品成分进行指认具有重要意义.基于B97-D/6-311++G(2d,2p)的密度泛函理论(DFT)计算,我们系统地探索了构成水合物的两种标准水笼(51262和51264)包络十八种不同烷烃客体分子的稳定性.从计算结果可以看出,除了3-甲基戊烷和2,3-二甲基丁烷两个烷烃客体分子,其它16个烷烃客体分子都可以被容纳在51262笼中;但是与51262笼不同,十八种烷烃客体分子都可以被容纳在尺寸较大的51264笼中.同时,我们也模拟了五种直链烷烃和四种环状烷烃在51262和51264笼中相应的谱学特征,从拉曼谱图上可以看出,随着碳原子数量的增多,直链烷烃客体分子C―H键伸缩振动区的多数拉曼谱带向高波数移动,而环状烷烃客体分子C―H键伸缩振动区的拉曼谱带则向低波数移动.这些结果为实验上通过拉曼谱测量指认水合物矿藏的成分提供理论参考.     

TinC2n(n=1-6)分子簇的量子化学从头算研究

用量子化学从头计算方法研究了TinC2n(n=1-6)分子簇的几何构型和电子结构。这些TinC2n分子簇以TiC2为结构单元, 通过C-C或Ti-C键进一步连接而逐渐长大。研究结果可以较好地解释实验现象, 并说明Metcars的形成机理。     

C_(120)(NH_2)~+的电子结构和光谱的理论研究

用ＩＮＤＯ系列方法对Ｃ１２０ＮＨ２＋进行了理论研究，结果表明：质子化后的Ｃ１２０ＮＨ２＋较稳定，且离子中两碳笼间仍有弱的相互作用，Ｃ１２０ＮＨ２＋可以失去质子成为中性分子．Ｃ１２０ＮＨ２＋的电子光谱与Ｃ１２０ＮＨ的光谱相似．     

硅-硫团簇(SiS2)+n(n=1-3)的结构和振动光谱的量子化学研究

用密度泛函（ＤＦＴ）方法研究了硅硫团簇（ＳiＳ２）n＋（n＝１－３）的各种可能的几 何构型和电子结构,并计算了相应的振动光谱,得到（ＳiＳ２）n＋的生长规律,由此预测了（ＳiＳ２）n＋团簇的形成机理。     

层状结构杂合物(C_nH_(2n+1)NH_3)_2NiCl_4(n=4,8,12)的合成与表征（英文）

采用低温固相合成法制备了3种有机/无机杂合物(CnH2n+1NH3)2NiCl4(n=4,8,12),通过元素分析、X射线粉末衍射、红外光谱和紫外-可见吸收光谱对杂合物进行了表征.实验结果表明,利用低温固相合成法可成功制备杂合物(CnH2n+1NH3)2NiCl4(n=4,8,12),3种产物均具有明显的层状结构且分别属于单斜晶系、六方晶系和正交晶系.     

丙烷分子的价轨道(2b2)电子的动量分布测量

电子动量谱学（EMS）是在原子、分子和固体物理中研究电子结构的一种强有力的工具，它基于运动学条件完全确定的（e，2e）碰撞电离反应[1-3]．本文报告用高分辨电子动量谱仪首次测量得到丙烷门3H8）分子的价轨道电子（252）的动量分布·丙烷（C3Hs）价轨道电子的动量分布实验是     

硅-硫团(SiS_2)_n~+(n=4,5)的结构和振动光谱的量子化学研究

用密度泛函（ＤＦＴ） 方法研究了硅硫团簇（ＳｉＳ２） ｎ＋（ ｎ ＝ ４ ,５） 的各种可能几何构型和电子结构,并计算了相应的振动光谱,得到了（ＳｉＳ２）ｎ＋ 的形成规律,即（ＳｉＳ２）ｎ ＋ 以硅、硫交错形成四元环链的形式增长．     

High Resolution Electron Momentum Spectroscopy Study on Ethanol: Orbital Electron Momentum Distributions for Individual Conformers

The outer-valence binding energy spectra of ethanol in the energy range of 9-21 eV are measured by a high-resolution electron momentum spectrometer at an impact energy of 2.5 keV plus the binding energy. The electron momentum distributions for the ionization peaks corresponding to the outer-valence orbitals are obtained by deconvoluting a series of azimuthal angular correlated binding energy spectra. Comparison is made with the theoretical calculations for two conformers, trans and gauche, coexisting in the gas phase of ethanol at the level of B3LYP density functional theory with aug-cc-pVTZ basis sets. It is found that the measured electron momentum distributions for the peaks at 14.5 and 15.2 eV are in good agreement with the theoretical electron momentum distributions for the molecular orbitals of individual conformers (i.e., 8a' of trans and 9a of gauche), but not in accordance with the thermally averaged ones. It demonstrates that the high-resolution electron momentum spectrometer, by inspecting the molecular electronic structure, is a promising technique to identify different conformers in a mixed sample.     

Observation of Interference Effects in (e, 2e) Electron Momentum Spectroscopy of SF6 (cited: 1)

Two-dimensional electron density map (2D map) of binding energy and relative azimuthal angle (i.e., momentum) for the outer-valence molecular orbitals of SF₆ has been measured by a highly sensitive electron momentum spectrometer with noncoplanar symmetric geometry at the impact energy of 1.2 keV plus binding energy. The experimental electron momentum profiles for the relevant molecular orbitals have been extracted from the 2D map and interpreted on the basis of the quantitative calculations using the density functional theory with B3LYP hybrid functional. For the outermost F2p nonbonding orbitals of SF₆, the interference patterns are clearly observed in the ratios of the electron momentum profiles of molecular orbitals to that of atomic F2p orbital.     

CF2BrCl分子近域轨道的电子动量谱学研究

The frontier molecular orbitals (HOMO and NHOMO) of CF2BrCl molecule have been firstly investigated by (e,2e) electron momentum spectroscopy. The experimental momentum profiles are compared with the theoretical profiles employing Hartree-Fock and density functional theory with 6-31G and 6-311+G(d) basis sets. Both HF and DFT calculations using 6-311+G(d) basis set can well describe the experiment, whereas those calculated using 6-31G basis set largely underestimate the experiment at the low momentum region. Furthermore, orbital electron density images show that HOMO and NHOMO have a mixed character of the bromine and chlorine lone pairs.     

Electron Momentum Spectroscopy of Outer Valence Orbitals of 2-Fluoroethanol

The binding energy spectra and electron momentum distributions for the outer valence molecular orbitals of gaseous 2-fluoroethanol have been measured by the non-coplanar asymmetric (e, 2e) spectrometer at impact energy of 2.5 keV plus binding energy. The quantitative calculations of the ionization energies and the relevant molecular orbitals have been carried out by using the outer-valence Green’s function method and the density functional theory with B3LYP hybrid functional. The observed ionization bands in binding energy spectra, as well as the previous photoelectron spectrum which was not assigned, have been assigned for the first time through the comparison between experiment and theory. In general, the theoretical electron momentum distributions calculated by B3LYP method with aug-cc-pVTZbasis set are in line with the experimental ones when taking into account the Boltzmannweighted thermo-statistical abundances of five conformers of 2-fluoroethanol.     

Electron Momentum Spectroscopy of Ethanethiol Complete Valence Shell

The binding energy spectra and electron momentum distributions for the complete valence orbitals of ethanethiol were measured for the first time by binary (e, 2e) electron momentum spectroscopy employing non-coplanar symmetric kinematics at an impact energy of 1200 eV plus binding energy. The experimental results are generally consistent with the theoretical calculations using density functional theory and Hartree-Fock methods with various basis sets. A possible satellite line at 17.8 eV in binding energy spectrum was observed and studied by electron momentum spectroscopy.     

精确的甲烷分子价轨道的电子动量谱学研究

电子动量谱学（EMS）已发展成为探测原子分子电子结构的强有力工具．借助电子动量谱学可获得精确的分子轨道电子密度分布，并能提供非常详细的电子运动和电子关联信息．分子电子密度分布和电子运动的详细了解对分子的识别和化学活性的理解非常重要，并且也有助于计算机辅助的分     

Electron Momentum Spectroscopy Study on Inner Orbitals of Methyl iodide

The binding energy spectrum and electron momentum profiles of the inner orbitals of methyl iodide have been measured using an electron momentum spectrometer at the impact energy of 1200 eV plus binding energy. Two peaks in the binding energy spectrum, arising from the spin-orbit splitting, are observed and the corresponding electron momentum profiles are obtained. Relativistic density functional calculations are performed to elucidate the experimental electron momentum profiles of two spin-orbit splitting components, showing agreement with each other except for the intensity in low momentum region. The measured high intensity in the low momentum region can be further explained by the distorted wave calculation.     

Electron Momentum Spectroscopy Investigation on Electronic Structure of Iso-dichloroethylene Valence Shell

Here an electron momentum spectroscopy study on the electronic structure of valence shell of iso-dichloroethylene molecule is reported. The experiment is carried out with a binary (e, 2e) spectrometer at incident electron energy of 1200 eV, employing noncoplanar symmetric arrangement. The binding energy spectra and electron momentum distributions (EMDs) of iso-dichloroethylene valence shell have been obtained. Theoretical EMDs are predicted with both Hartree-Fock and density functional theory methods, generally indicating good agreements with the measurement results. The interference effect is observed to significantly influence the EMDs of 2a₂ and 5b₂ Cl lone-pair orbitals.     

环己烯分子2b和3a轨道的电子动量谱学研究

The electron momentum profile for inner valence orbitals 2b and 3a of cyclohexene (C6H10) was firstly studied by the binary (e,2e) electron momentum spectroscopy (EMS), at the impact energy of 1200 eV plus binding energy using symmetric non-coplanar kinematics. The complete valence shell binding energy spectrum of C6H10 was also obtained. The experimental momentum profile of the summed orbitals was compared with Hartree Fock (HF) and density functional theory (DFT) methods with various basis sets. The experimental measurement was well described by the HF and DFT calculations except for the low-p region (p<0.25 a.u.). Experimental small “turn-up” effects of momentum profile in the low-p region could be due to the distorted wave effects.