Fluorescein有机薄膜在Ag(110)面上的生长研究

利用紫外光电子能谱(UPS)对在Ag(110)表面上荧光素(fluorescein)的生长进行研究. 研究表明, 与fluorescein分子轨道有关的4个特征峰分别位于费米能级以下2.70, 3.80, 7.40和9.80 eV处. 角分辨紫外光电子能谱(ARUPS)测量结果表明, fluorescein分子的三苯环平面平行衬底平面, 分子的C=O轨道轴向接近于[1-10]晶向.     

银(110)表面苝有序薄膜电子态的研究

运用紫外光电子能谱(UPS)和低能电子衍射(LEED)技术,对银(110)表面上有机分子苝（perylene）的生长进行了研究.有机分子价带的4个特征峰分别位于费米能级以下3.5、4.8、6.4和8.5 eV处.当有机薄膜约为单分子层(厚度为0.3 nm)时, 苝在银(110)表面上形成C(6×2)的有序结构.角分辨紫外光电子能谱(ARUSP)的测量显示:在界面处的苝分子平面平行于衬底.苝在银(110)表面稳定性很高,随着对衬底加热，有机材料发生脱附,在140 ℃以下没有观察到分解现象.     

用同步辐射光研究CO在Cs/Ru(100)表面的吸附

(CO+Cs)/Ru(1010)共吸附的体系中,CO分子由于受CS原子强烈影响,分子轨道发生重新杂化组合.CO分子原来在清洁Ru(1010)表面上结合能位于7.5eV处相重叠的5σ和1π轨道对应谱峰分裂为两峰,结合能分别位于6.3和7.8eV处.其中6.3eV处的谱峰来自CO分子1π轨道的一支,它显示出该分子轨道沿衬底<0001>晶向的镜面反对称性.CO分子1π轨道的另一支和5σ轨道在结合能7.8eV处相重叠.     

苯氰基衍生物气相HeI紫外光电子能谱研究

气相Hel（21．22eV）紫外光电子能谱（UPS）能从孤立分子的分子轨道特性上，给出研究分子的轨道能量、电子结构以及成键特性的大量信息．UPS谱的特性揭示了被电离分子轨道的成键性质，而量子化学计算能正确地指认UPS谱带的归属，从而化合物的UPS研究从分子轨道的属性上提供了研究体系的实验和理论基础．苯基腈（C6H5CN）的UPS已有过研究［1-3］，但作为系列分子的间-二氰基苯（1）、对-二氰基苯（2）、1；2，4，5-四氰基苯（3）的HeI光电子能谱未见报道．这一系列分子的特点是-CN取代的数目和位置不同，通过这些分子UPS的研究找…     

N-(2-溴乙基)咔唑与N-乙烯基咔唑的气相HeI紫外光电子 能谱与电子结构研究

首次报道了N-(2-溴乙基)咔唑和N-乙烯基咔唑的气相HeI紫外光电子能谱(UPS),借助于Gaussian94采用RHF/6-31G基组优化几何构型,并用RHF/6-31G^*基组计算分子轨道及能级.在对咔唑和N-烷基咔唑系列分子UPS电离能变化规律研究的基础上,对这2个分子的UPS谱带给予指认,并讨论其电子结构.结果表明N-(2-溴乙基)咔唑的UPS谱与N-烷基咔唑的不同之处是在10.295,10.540eV处出现2个Br原子的孤对轨道;N-乙烯基咔唑的UPS谱带与咔唑的相比,电离能变化的特殊性说明乙烯基与咔唑环共平面。     

分子内孤对(n)轨道间相互作用的又一例证——某些杂氮环己烷系列化合物的气相H_eI_α紫外光电子能谱(UPS)研究

人们知道,原子和分子的气相紫外光电子能谱(UPS)谱带的分离结构是电子能级量子化的反映.谱峰相应的电子结合能(或电离能)是正则(自洽场)分子轨道计算方法给出的本征值(-ε_i),所以UPS是目前用以获得原子或分子能级直接量度的最好技术.就是说:量子化学理论可以提供UPS解译的必要模型,而UPS谱本身反过来又可以检验分子轨道理论的正确性,并作为各种近似分子轨道理论计算中经验参数化(如SPINDO)的基础.因而UPS     

己烯在Ru(1010)表面价带电子特性研究

在200 K以下己烯（C6H12）可以在Ru()表面上以分子状态稳定吸附.偏振角分辨紫外光电子谱（ARUPS）结果表明,己烯分子在垂直于衬底表面并沿衬底表面<>晶向的平面内,己烯分子的轴向沿<>晶向倾斜.随着衬底温度的提高,到200 K以上,己烯分解生成新的碳氢化合物.己烯分解后,πCH分子轨道能级向高结合能方向移动了0.2 eV,同时己烯中C的1s能级向低结合能方向移动了 0.3 eV.     

由NO分子从头计算结果和紫外光电子能谱确定NO的分子结构

对于NO分子轨道的能级次序现有两种不同的说法,不少人根据NO与O_2~+是等电子体,由O_2~+分子的能级次序确定NO分子组态。本文用NO和O_2~(+)从头计算结果以及NO的紫外光电子能谱相结合的方法说明NO的5σ轨道是弱成键轨道,5σ的轨道能稍高于1π轨道能,也就是说NO的能级次序是与N_2分子相同的;NO与O_2~+虽是等电子体,但是能级次序并不相同,因此由O_2~+的能级次序确定NO分子的电子组态是不妥的。     

乙烯在Ru(1010)表面价带电子特性研究

在200K以下乙烯(C2H4)可以在Ru(1010)表面上以分子状态稳定吸附,200K以上乙烯发生了脱氢分解反应生成乙炔(C2H2).乙烯分解生成乙炔后,σCC和σCH分子轨道能级向高结合能方向分别移动了0.5和1.1 eV.偏振角分辨紫外光电子谱(ARUPS)结果表明:在Ru(1010)表面上,乙烯和脱氢反应后生成的乙炔分子的C-C键轴都不平行于表面,而是沿表面(0001)晶向倾斜.     

哌嗪二酮的气相Hel光电子能谱及其量化计算

给出了哌嗪二酮的气相HeI紫外光电子能谱(UPS), 并进行了化合物分子的HAM/3, MNDO, MINDO/3, INDO, CNDO/2和EHMO等量子化学计算研究. UPS谱低电离能(<11.00 eV)区的四重峰被指认为分子体系中氧-氧, 氮-氮原子孤对轨道间的通过键相互作用导致的分裂峰. 表明HAM/3和MNDO计算法是预指该化合物实验电离能正确次序、轨道对称性类型以及通过键相互作用导致分裂大小的较好方法.     

C2H2在Ru(1010)表面上的分子轨道对称性

利用角分辨紫外光电子能谱对低温下（160 K）乙炔（C2H2）气体在Ru()表面的吸附 进行了研究.实验结果表明：乙炔的C-C轴并不平行于衬底表面, C-C轴在<0001>晶向和表 面法线组成的平面内有一定的倾斜.与气相乙炔分子不同,在Ru()表面吸附的乙炔分子的C-H 轴不是沿C-C轴向.     

The growth of perylene on Ru(0001)

The structure of perylene adsorbed on Ru(0001) surface has been studied by ultraviolet photoemission spectroscopy (UPS) and low-energy electron diffraction. An ordered p(4x4) structure is observed from a monolayer (about 4 A thickness) of the perylene on Ru(0001) surface. UPS measurements show the molecular features, from the perylene multiplayer, between 2 and 10 eV below the Fermi level. Angle-resolved ultraviolet photoemission spectroscopy measurements suggest that the perylene molecular plane is parallel to the substrate. Temperature dependent UPS measurements show that the perylene multilayer is stable on Ru(0001) surface up to 125 degrees C. The desorption of the multilayer and the decomposition of the monolayer are observed above 125 degrees C.     

A synchrotron-based photoemission study of the MoO3∕Co interface

The electronic structures at the MoO(3)∕Co interface were investigated using synchrotron-based ultraviolet and x-ray photoelectron spectroscopy. It was found that interfacial chemical reactions lead to the reduction of Mo oxidation states and the formation of Co-O bonds. These interfacial chemical reactions also induce a large interface dipole, which significantly increases the work function of the cobalt substrate. In addition, two interface states located at 1.0 and 2.0 eV below the Fermi level are identified. These two states overlap at film thickness of between 2-4 nm, which suggests the MoO(3) intermediate layer may facilitate ohmic charge transport.     

Study on the interaction between tetracene and Cu(110) surface

The electronic structure of tetracene on Cu (110) surface has been studied by using ultraviolet photoemission spectroscopy (UPS). The emission features from the organic molecule are located from 1 to 10 eV below the Fermi level, and they shift in binding energy with increasing the coverage of the organic material. For the surface with multilayer of tetracene, six well-resolved features were found at 1.90, 3.40, 4.70, 5.95, 6.95, and 9.15 eV below the Fermi level, respectively. On the surface with a lower coverage of tetracene, angle-resolved UPS measurements suggest that the molecular plane is parallel to the substrate. Density functional theory calculation confirms the flat-lying adsorption mode and shows that the tetracene molecule prefers to be adsorbed on the long bridge site with its long axis in the [110] azimuth.     

Surface/interface electronic structure in C(60) anchored aminothiolate self-assembled monolayer: an approach to molecular electronics

Electronic structure in self-assembled monolayers (SAMs) of C(60) anchored 11-amino-1-undecane thiol (C(60)-11-AUT) on Au(111) was studied by means of ultraviolet photoelectron spectroscopy and hybrid density functional theory calculations. Valence band features of the molecular conformation revealed the interface electronic structure to be dominated by sigma(S-Au), localized at the thiolate anchor to Au. Formation of a localized covalent bond as a result of hybridization between N P(z) orbital of -NH(2) group of the thiolate SAM and the pi level of C(60) resulted in a symmetry change from I(h) in C(60) to C1 in C(60)-11-AUT SAM. Appearance of low, but finite amplitude surface electronic states of bonded C(60), much beyond the Fermi level, ruled out Au-C(60) end group contact. The band gap E(g) of the SAM, determined to be 2.7 eV, was drastically reduced from the insulating alkanethiol SAMs ( approximately 8.0 eV) and fell intermediate between the C(60) ground state (N electrons, 1.6 eV) and C(60) solid (N+/-1 electrons, 3.7 eV).     

Electronic and chemical properties of tin-doped indium oxide (ITO) surfaces and ITO/ZnPc interfaces studied in-situ by photoelectron spectroscopy

The chemical and electronic properties of tin-doped indium oxide (ITO) surfaces and its interface with zinc phthalocyanine (ZnPc) were investigated using photoelectron spectroscopy partly excited by synchrotron radiation from the BESSY II storage ring. Preparation and analysis of ITO and ITO/ZnPc layer sequences were performed in-situ without breaking vacuum. The Fermi level position at the ITO surface varies strongly with oxygen content in the sputter gas, which is attributed to an increase of surface band bending as a consequence of the passivation of the metallic surface states of ITO. The shift of the Fermi level is accompanied by a parallel increase of the work function from 4.4 to approximately 5.2 eV. No changes in the surface dipole are observed with an ionization potential of I(P) = 7.65 +/- 0.1 eV. The barrier height for hole injection at the ITO/ZnPc interface does not vary with initial ITO work function, which can be related to different chemical reactivities at the interface.     

Surface state and composition of a disperse Pd catalyst after its exposure to ethylene

Pd black was exposed to ethylene alone or in its mixture with hydrogen at 300 and 573 K. The samples were investigated by X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Room temperature introduction of C(2)H(4) (also in the presence of H(2)) induced a binding-energy (BE) shift in the Pd 3d doublet and changed its full width at half-maximum (fwhm). The UPS features indicate shifting of electrons from the Pd d-band to Pd-H, Pd-C, and even Pd-OH species. Vinylidene (BE approximately 284.1 eV) may be the most abundant individual surface species on disperse Pd black, along with carbon in various stages of polymerization: "disordered C" (BE approximately 284 eV), graphite (approximately 284.6 eV), and ethylene polymer (approximately 286 eV), and also some "atomic" C (BE approximately 283.5 eV). Introduction of H(2) followed by ethylene brought about stronger changes in the state of Pd than exposure in the reverse sequence. This may indicate that the presence of some surface C may hinder the decomposition of bulk PdH. Formation of Pd hydride was blocked when ethylene was introduced prior to H(2). The C 1s intensity increased, the low-binding-energy C components disappeared, and graphitic carbon (BE approximately equal to 284.6 eV) prevailed after ethylene treatment at 573 K. The loss of the Pd surface state and "PdH" signal were observed in the corresponding valence band and UPS spectra. Hydrogen treatment at 540 K was not able to decrease the concentration of surface carbon and re-establish the near-surface H-rich state. UPS showed overlayer-type C in these samples. The interaction of Pd with components from the feed gas modified its electronic structure that is consistent with lattice strain induced by dissolution of carbon and hydrogen into Pd, as indicated by the d-band shift and the dilution of the electron density at E(F).