CO与K在Fe(110)面上共吸附的角分辨紫外光电子谱

用角分辨偏振紫外光电子谱对CO与K在Fe(110)表面上共吸附进行了研究。CO与K共吸附的Hel紫外光电子谱与清洁表面上CO的结果相比,在结合能为6.3eV处出现了一个新的谱峰。偏振紫外光电子谱的分析表明:相关的初态有一对称面,此面平行于衬底〈001〉方向。Hell紫外光电子谱中,CO的4σ态(4α₁)强度随入射角改变的结果表明CO依然近似于直立在有K覆盖的Fe表面上。 关键词：     

CO和K在Fe(110)面共吸附的高分辨电子能量损失谱研究

本工作用高分辨电子能量损失谱(HREELS)对Fe(110)面CO和K的共吸附进行了研究,发现存在三种CO吸附状态,表现为不同的C—O振动频率,当θ_k=0.03时,存在与K近程、中程和远程三种不同相互作用的CO,当θ_k=0.06时,与K远程作用的CO吸附状态消失,近程作用的CO占据主要地位,所有CO的C—O振动频率均随CO暴露量的增加向高波数方向移动,随着表面K的增多,CO—Fe振动损失峰消失。 关键词：     

Growth of CuO chains on Ag(110) surfaces

The (AgO) chains grown along the 〈001〉 direction on Ag(110) disappeared by the reaction with Cu atoms at room temperature, and new one-dimensional chains grew in the 〈110〉 direction. The STM images at different bias potentials suggest the growth of (CuO) chains in the 〈110〉 direction on the Ag(110) surface. The (CuO) chains on the Ag(110) surface disappeared by heating to 470 K, but they reappeared by exposing to O₂ at room temperature.     

As吸附在InP(110)表面电子性质的理论研究

利用形式散射的格林函数方法，研究了As在InP(110)表面不同吸附结构的电子性质.体材料采用实用的经验紧束缚近似方法的哈密顿，分别计算了As-P交换作用和形成外延连续层结构表面态的性质，指出了表面态和表面共振态产生的原因.在计算中，一些表面紧束缚相互作用参数进行了调整，所得结果好于其他理论方法. 关键词：     

Sb吸附在InP(110)表面电子性质的理论研究

利用形式散射的格林函数方法,研究了Sb在InP(110)表面单层吸附时的电子性质．分别计算了清洁的InP(110)弛豫表面和InP(110)-Sb(1ML)体系的表面态的性质,指出了表面态和表面共振态产生的原因．所得结果与实验相符. 关键词：     

并五苯分子在Ag(110)表面成膜过程中的结构研究

采用低能电子衍射原位研究了并五苯分子（C₂₂H₁₄）在Ag(110)单晶表面的生长，观察了在初期沉积过程及随后基底变温过程中分子层结构的形成和变化.室温下并五苯分子在Ag(110)基底表面具有高的迁移性，从开始无序的亚单层膜结构逐渐形成有序的单层膜结构．实验和理论分析表明：并五苯分子平铺在Ag(110)表面，形成了与基底构成有关的有序结构，存在沿基底晶向成镜面对称的两种畴界取向，在基底温度从室温升高到接近并五苯升华温度的过程中，基底上的有序分子层结构保持稳定不变 关键词： 并五苯 低能电子衍射图案 分子层结构 Ag(110)     

吸附原子在Ag,Pt,Au(110)表面上的自扩散现象

采用表面嵌入势，用静态计算和分子动力学方法研究了Ag,Pt,Au单个吸附原子在(110)表面上的自扩散现象.分别给出了跳跃机制和交换机制所对应的能量变化曲线及相关原子的运动轨迹，分析了这三种不同金属(110)表面上的自扩散特点，结果与分子动力学模拟及有关的实验结果相符合.     

Ag(110)表面吸附酞菁铜分子的紫外光电子谱研究

用紫外光电子能谱(UPS)研究了酞菁铜分子在Ag(110)单晶表面上的吸附，随着酞菁铜分子覆盖度增加，衬底Ag的3d电子信号逐渐减弱，在此能带区域出现两个新的谱峰，这两个与吸附有机分子轨道有关的谱峰的束缚能分别为4.45 和6.36 eV.随着覆盖度的增加，在结合能为1.51和9.20 eV处又出现了两个谱峰，它们同样来自吸附有机分子的轨道.随着覆盖度的继续增加，上述四个谱峰的强度逐渐增加，其能量位置均发生了明显的偏移.根据角分辨光电子能谱的实验结果，酞菁铜分子的分子平面基本与衬底表面平行.密度泛函理论计     

Ag(110)表面吸附酞菁铜分子的紫外光电子谱研究

用紫外光电子能谱(UPS)研究了酞菁铜分子在Ag(110)单晶表面上的吸附,随着酞菁铜分子覆盖度增加,衬底Ag的3d电子信号逐渐减弱,在此能带区域出现两个新的谱峰,这两个与吸附有机分子轨道有关的谱峰的束缚能分别为4.45 和6.36 eV.随着覆盖度的增加,在结合能为1.51和9.20 eV处又出现了两个谱峰,它们同样来自吸附有机分子的轨道.随着覆盖度的继续增加,上述四个谱峰的强度逐渐增加,其能量位置均发生了明显的偏移.根据角分辨光电子能谱的实验结果,酞菁铜分子的分子平面基本与衬底表面平行.密度泛函理论计 关键词： 酞菁铜 紫外光电子谱 吸附电子态 密度泛函理论     

High-resolution study of dipole-active vibrations at the Ag(110) (n × 1)O surface

Atomic chemisorption of oxygen on Ag(110) at room temperature has been studied by high resolution electron energy loss spectroscopy (HREELS). It is well known that upon increasing exposure the LEED pattern sequentially changes as (n × 1), with n = 7, 6, ⋯ 2. We present the first dear evidence that the oxygen vibration frequency changes from (ω⊥ = 38.5 meV (n = 7) to 40.9 meV (n = 2). Simultaneously the surface phonon observed on Ag(110) at 13.2 meV shifts to 17.0 meV (at n = 2) and a second phonon appears at lower energies (8.7 meVatn = 2). We discuss implications of our data for the formation of the (n × 1) added row structure.     

C2H2,C2H4与K在Ru(1010)表面上共吸附的UPS研究

利用紫外光电子谱(UPS)对乙烯(C₂H₄)和乙炔(C₂H₂)气体在Ru(1010)表面的吸附及与K的共吸附进行了研究,实验结果表明:当衬底温度超过200K,乙烯即发生脱氢反应后,σ_CH和σ_CC能级均向高结合能方向移动.在室温下,σ_CH和σ_CC能级位置与乙炔在Ru(1010)表面的吸附时的分子能级完全一致.乙烯发生脱氢反应后的主要产 关键词： 乙烯 乙炔 钾 Ru(1010)表面     

用HREELS,XPS,LEED研究Al-GaAs(100)(4×1)界面反应

高分辨率电子能量损失谱(HRFELS)能直接判定Al-GaAS(100)界面反应的生成物。本文结合X射线光电子能谱(XPS)的测量,采用HREELS来测量界面的禁带宽度,研究了Al-GaAs(100)(4×1)界面的形成过程。结果判定了室温下Al-GaAs(100)界面生成的为AlAs。而退火后,界面上生成AlCaAs合金。实验中还用低能电子衍射(LEED)观察了室温下Al在GaAs(100)(4×1)面上的淀积过程,发现随着Al淀积量的增加,表面是从无序到有序转化的。 关键词：     

用ARUPS和HREELS研究GaP(111)面的表面态

本文利用角分辨紫外光电子能谱(ARUPS)和高分辨率电子能量损失谱(HREELS)研究Ar⁺刻蚀退火处理的GaP(111)面表面态。发现与P原子悬挂键有关的本征满表面态在Г点位于价带顶下0.6eV处,而缺陷引入的空表面态位于价带顶上1.1eV处(Г点)。空表面态引起n型样品表面能带发生1.36eV弯曲。     

The Ag(111)/K system studied with ellipsometry,LEED and EELS

Ellipsometry in the photon range 0.6–4 eV has been used in combination with LEED and EELS to study K adsorbed on Ag(111). The observations made with the two latter techniques are consistent with the view of a nearly ionic adsorbate at low coverages and an almost neutral metallic overlayer at high coverages. The influence of adsorption of monolayers on the optical absorption spectrum has been found to be significant, thus giving further support to the use of ellipsometry as a spectroscopic tool to study adsorption systems.     

用低能电子衍射研究氢在Si(100)表面吸附引起的相变

描述了用低能电子衍射(LEED)研究不同温度下在Si(100)-c(8×8)表面吸氢引起的一系列相变过程。实验发现:在液氮温度下,在Si(100)-c(8×8)表面连续吸氢将引起表面经Si(100)-(4×1)-H向(2×1)-H最终向(1×1)-H转变;而在从700℃到室温间的不同温度下饱和吸氢,实验中观察到:Si(100)-c(8×8)表面将先转变至Si(100)-c(4×4)-H,然后至(2×1)-最终至(1×1)-H。     

An XPS and UPS study of the interaction of oxygen with sodium-dosed Ag(110)

The adsorption of Na and the coadsorption of Na and O₂ on Ag(110) have been studied by XPS and UPS. Adsorption of Na results in a rapid decrease in the work function. Δφ reaching a limiting value of ?2.0 eV at θ_Na = 0.5 and thereafter remaining constant. In the coverage range 0 < θ_Na <1 adsorption of O₂ onto the Na dosed surface always results in an increase in the work function to an almost constant value of Δφ ~ ?1 eV. At the same time the XPS data show that the Na/O stoichiometry of the oxygen saturated surface remains essentially constant and independent of the initial Na dose. Calibration experiments using sodium formate as a standard compound indicate that this surface phase has the stoichiometry Na₂O. For θ_Na > 1 there is a sharp change in behaviour; the work function of the oxygen saturated surface begins to decrease rapidly, and eventually falls below the value for the Na covered surface itself at θ_Na ~ 1.5. The XP spectrum now shows the appearance of a new oxygen peak which increases in intensity as θ_Na increases beyond unity. The UP spectra indicate that the binding energy of the surface orbital derived from Na (3s) is increased by ~6.7 eV as compared with the free atom value, and the emission at ~3 eV below E_F, which is associated with surface oxygen is not greatly affected by the presence of Na. These results are discussed against the background of information already available from LEED, Auger, and thermal desorption studies, and we attempt to give a consistent interpretation of the properties of the system at coverages both below and above one monolayer.