DNA topology on an increase in positive writhing number of DNA: conformation changes in the time course of cis-diamminedichloroplatinum(II)-DNA adducts

We show that the topological significance of the gel mobility of cis-diamminedichloroplatinum(II) (DDP)-closed circular DNA (ccDNA) adducts decreases with reaction time, until a point at which it joins relaxed DNA, and that the mobility of the adducts increases again. There is no relationship between the relative length of the adducts and the gel mobility. Although the significance of the decrease of gel mobility is due to the unwinding of cis-DDP-DNA (or trans-DDP-DNA) adducts, the conformational significance of the subsequent increase in mobility is unclear. To elucidate the conformational significance for unwinding of the adducts, we measured the writhing number (Wk) of the adducts using electron microscopy and analyzed the topological states of cis-DDP (or trans-DDP) adducts based on the White rule, Lk=Wk+Tk. Where, Lk and Tk represent the linking and twisting number in the ring, respectively. From the data, we found that the Wk of cis-DDP-ccDNA adducts in comparison with trans-DDP-ccDNA adducts increases from a negative to a positive number with time. This suggests that cis-DDP plays a role in the change of the topological state of ccDNA. In the abstraction of platinum from the adducts with CN- ion, the differences in both topological states may explain why Pt in trans-DDP is abstracted more easily than in cis-DDP. To explain the abstraction of Pt ion, we also discuss the findings based on the thermodynamic cycle in a intermolecular crosslink model Pt(NH3)2(guanine)2(2+)-->Pt(CN)4(2-) using the Pt parametrized PM3 method.     

Adsorption and mobility of a lipase at a hydrophobic surface in the presence of surfactants

With the aim of being able to manipulate the processes involved in interfacial catalysis, we have studied the effects of a mixture of nonionic/anionic surfactants, C12E6/LAS (1:2 mol %), on the adsorption and surface mobility of a lipase obtained from Thermomyces lanuginosus (TLL). Surface plasmon resonance (SPR) and ellipsometry were used to analyze the competitive adsorption process between surfactants and TLL onto hydrophobic model surfaces intended to mimic an oily substrate for the lipase. We obtained the surface diffusion coefficient of a fluorescently labeled TLL variant on silica silanized with octadecyltrichlorosilane (OTS) by fluorescence recovery after photobleaching (FRAP) on a confocal laser scanning microscope. By means of ellipsometry we calibrated the fluorescence intensity with the surface density of the lipase. The TLL diffusion was measured at different surface densities of the enzyme and at two time intervals after coadsorption with different concentrations of C12E6/LAS. The surfactant concentrations were chosen to represent concentrations below the critical micelle concentration (CMC), in the CMC region, and above the CMC. The apparent TLL surface diffusion was extrapolated to infinite surface dilution, D0. We found that the presence of surfactants strongly modulated the surface mobility of TLL: with D(0) = 0.8 x 10(-11) cm2/s without surfactants and D0 = 13.1 x 10(-11) cm2/s with surfactants above the CMC. The increase in lipase mobility on passing the CMC was also accompanied by a 2-fold increase in the mobile fraction of TLL. SPR analysis revealed that surface bound TLL was displaced by C12E6/LAS in a concentration-dependent manner, suggesting that the observed increase in surface mobility imparts bulk-mediated diffusion and so-called rebinding of TLL to the surface. Our combined results on lipase/surfactant competitive adsorption and lipase surface mobility show how surfactants may play an important role in regulating interfacial catalysis from physiological digestion to technical applications such as detergency.     

Effect of topological asymmetry on the electrophoretic mobility of branched DNA structures with and without single-base mismatches

The electrophoretic mobility of three-arm star DNA structures with varying degrees of branch length asymmetry has been investigated in polyacrylamide (PAA) hydrogels. We report the effect of single-base mismatches, adjacent to the branch point, on the mobility of branched DNA with three different arm lengths. Branched DNA structures were formed using wild-type and mutated fragments of the p53 tumor suppressor gene, which is believed to play an important role in cancer development. Branching was directed at the site of several previously characterized mutations in exon 7 of p53. At a given gel concentration, the mobility of branched DNA with fully complementary base pairing is found to increase as the degree of branch length asymmetry is increased. Ferguson analysis of the gel electrophoresis data leads to a retardation coefficient that is strongly dependent on topology. This finding can be explained in terms of a minimum molecular cross-section for each molecule. Specifically, we show that structures with the smallest molecular cross-section can access more pores in the gel, which leads to higher mobility. Our results can also be understood by considering the rotational diffusivity of branched DNA. Asymmetric DNA stars with higher calculated rotational diffusivities also have higher mobilities. When a mutated base is present in junctions with low degrees of branch length asymmetry, adjacent to the branch point, the mobility increases in comparison to the fully complementary molecules. The reason for this increased mobility is unclear, here, we propose that the mismatched base introduces additional flexibility to the arm containing the mutation leading to higher conformational freedom and enhanced mobility in gels. When a mismatched base is present in junctions with high degrees of branch length asymmetry, the opposite result is obtained. Here, the mutated species has a lower mobility. This result is argued to arise from incomplete hybridization and/or frayed ends. Finally, we have shown that by using two of the branch point oligonucleotides as probe molecules, mutations known to occur at specific sites can be detected through the mobility shift. If the sequences of the probe chains are changed in a controlled manner, the location and base of the mutant can also be determined.     

一种用于高场非对称波形离子迁移谱系统的新型敞开式化学离子源

根据高场非对称波形离子迁移谱(FAIMS)系统的要求, 本文提出了一种新型敞开式直流电晕放电化学离子源. 该离子源主要由内线电极、外筒电极和牵引电极组成, 内、外电极半径分别是0.08、2 mm. 筒壁电极上开有对称的4个槽, 用于通入样品和牵引离子. 质谱实验结果表明, 该离子源能够在敞开环境下很好地离子化丙酮、乙醇、苯胺、N,N-二甲基甲酰胺、甲基磷酸二甲酯(DMMP)、乙酸乙酯、甲酸、乙酸、苯酚等正、负电性物质. 静电计测试实验结果说明该离子源能够稳定地产生离子电流. 通过分析不同时刻的谱图发现, 在不同时间点上产生的主要离子相同, 具有很好的稳定性. 利用感应耦合等离子体(ICP)工艺在硅片上加工了该离子源, 从而验证了该结构可以由微机电系统(MEMS)加工技术实现. 该离子源具有体积小、结构简单、无辐射、工作稳定等特点, 不仅可以满足FAIMS系统的要求, 还可用于敞开式质谱、微型质谱仪、离子迁移谱(IMS)等仪器.     

蓝宝石衬底上化学气相沉积法生长石墨烯

化学气相沉积(CVD)法是制备大面积、高质量石墨烯材料的主要方法之一,但存在衬底转移和碳固溶等问题,本文选用蓝宝石衬底弥补了传统CVD法的不足。利用CVD法在蓝宝石衬底上生长石墨烯材料,研究生长温度对石墨烯表面形貌和晶体质量的影响。原子力显微镜(AFM)、光学显微镜(OM)、拉曼光谱和霍尔测试表明,低温生长有利于保持材料表面的平整度,高温生长有利于提高材料的晶体质量。研究氢气和碳源对蓝宝石衬底表面刻蚀作用机理,发现氢气对蓝宝石衬底有刻蚀作用,而单纯的碳源不能对衬底产生刻蚀效果。在1200 ℃下,直径为50 mm的晶圆级衬底上获得平整度和质量相对较好的石墨烯材料,室温下载流子迁移超过1000 cm²·V^-1·s^-1。     

衬底温度对Fe3N薄膜生长和磁性的影响

采用直流磁控溅射方法, 以Si(100) 单晶片为衬底, 在衬底温度为150～450 ℃的范围内得到了ε-Fe3N薄膜样品. 利用 XRD, SEM和VSM等表征手段, 研究了衬底温度对ε-Fe3N薄膜的生长和磁性的影响. 实验结果表明, 随着衬底温度的升高, 薄膜的生长速率、晶粒尺寸和单位质量磁化强度均增大, 而矫顽力呈现先增加后减小的变化趋势, 当衬底温度为350 ℃时, 矫顽力达到最大值18.72 kA/m, 可以认为此时薄膜样品的晶粒尺寸接近于交换作用长度.     

有机半导体图案化成膜中的马兰戈尼与咖啡环效应协同作用

有机场效应晶体管在柔性传感和显示驱动应用中展示出极大的潜力,但在大面积制备高性能有机薄膜及有机场效应晶体管方面仍面临大的挑战。本文介绍了一种利用等离子处理和马兰戈尼-咖啡环效应协同作用来图案化生长有机半导体薄膜的方法。经过对等离子体处理时间、混合溶剂的比例及溶液浓度等生长条件优化,在5 cm×5 cm的基片上得到了覆盖性较为完整的2,7-二辛基[1]苯并噻吩并[3,2-b]苯并噻吩(C8-BTBT)薄膜阵列。基于此薄膜构筑了底栅顶接触晶体管阵列,器件的平均迁移率达到7.9 cm~2·V~(-1)·s~(-1),阈值电压均小于-2 V,开关电流比大于10~4。本工作对未来大面积制备高性能有机半导体薄膜及晶体管具有一定的借鉴意义。     

Contact line mobility in liquid droplet spreading on rough surface

We quantitatively estimate the effect of the substrate roughness on the liquid droplet spreading. Since the droplet size is in the order of millimeters, the surface energy becomes the dominant factor. A nonequilibrium thermodynamics framework [Y.X. Gao, H. Fan, Z. Xiao, Acta Mater. 48 (2000) 863-874] seems feasible for describing the millimeter size droplet spreading on a solid substrate. Within the framework, there are two system constants, namely the mobilities of liquid/air surface and the triple joint contact line that need to be determined from experimental testing. In the present paper, we demonstrate the experimental process of determining the mobility of the contact line via a droplet spreading on a steel substrate. Particularly, we obtained the contact line mobility on a steel surface with various roughness values. It is shown that the mobility value is lower for a rougher surface.     

Conformational studies of bottle-brush polymers absorbed on a flat solid surface

The adsorption of a bottle-brush polymer end-grafted with one chain end of its backbone to a flat substrate surface is studied by Monte Carlo simulation of a coarse-grained model, that previously has been characterized in the bulk, assuming a dilute solution under good solvent conditions. Applying the bond fluctuation model on the simple cubic lattice, we vary the backbone chain length N(b) from N(b)=67 to N(b)=259 effective monomeric units, the side chain length N from N=6 to N=48, and set the grafting density to σ=1, i.e., parameters that correspond well to the experimentally accessible range. When the adsorption energy strength ? is varied, we find that the adsorption transition (which becomes well-defined in the limit N(b)→∞, for arbitrary finite N) roughly occurs at the same value ?(c) as for ordinary linear chains (N=0), at least within our statistical errors. Mean square end-to-end distances and gyration radii of the side chains are obtained, as well as the monomer density profile in the direction perpendicular to the adsorbing surface. We show that for longer side chains the adsorption of bottle-brushes is a two-step process, the decrease of the perpendicular linear dimension of side chains with adsorption energy strength can even be nonmonotonic. Also, the behavior of the static structure factor S(q) is analyzed, evidence for a quasi-two-dimensional scaling is presented, and consequences for the interpretation of experiments are discussed.     

拓扑绝缘体二维纳米结构与器件

拓扑绝缘体是一种全新的量子功能材料, 具有绝缘性体能带结构和受时间反演对称性保护的自旋分辨的金属表面态, 属于Dirac 粒子系统, 将在新原理纳电子器件、自旋器件、量子计算、表面催化和清洁能源等方面有广泛的应用前景. 理论和实验相继证实Sb₂Te₃, Bi₂Se₃和Bi₂Te₃单晶具有较大的体能隙和单一Dirac 锥表面态, 已经迅速成为了拓扑绝缘体研究中的热点材料. 然而, 利用传统的高温烧结法所制成的拓扑绝缘体单晶块体样品常存在大量本征缺陷并被严重掺杂, 拓扑表面态的新奇性质很容易被体载流子掩盖. 拓扑绝缘体二维纳米结构具有超高比表面积和能带结构的可调控性, 能显著降低体态载流子的比例和凸显拓扑表面态, 并易于制备高结晶质量的单晶样品, 各种低维异质结构以及平面器件. 近年来, 我们一直致力于发展拓扑绝缘体二维纳米结构的控制生长方法和物性研究. 我们发展了拓扑绝缘体二维纳米结构的范德华外延方法, 实现了高质量大比表面积的拓扑绝缘体二维纳米结构的可控制备, 并实现了定点与定向的表面生长. 开展拓扑绝缘体二维纳米结构的谱学研究, 利用角分辨光电子能谱直接观察到拓扑绝缘体狄拉克锥形的表面电子能带结构, 发现了拉曼强度与位移随层数的依赖关系. 设计并构建拓扑绝缘体纳米结构器件, 系统研究其新奇物性, 观测到拓扑绝缘体Bi₂Se₃表面态的Aharonov-Bohm (AB)量子干涉效应等新奇量子现象, 通过栅电压实现了拓扑绝缘体纳米薄片化学势的调控, 并将拓扑绝缘体纳米结构应用于柔性透明导电薄膜. 本文首先简单介绍拓扑绝缘体的发展现状, 然后系统介绍我们开展的拓扑绝缘体二维纳米结构的范德华外延生长、谱学、电学输运特性以及透明柔性导电薄膜应用的研究, 最后对该领域所面临的机遇和挑战进行简要的展望.     

Electrophoresis and electric conduction in a salt-free suspension of charged particles

The electrophoresis and electric conduction of a suspension of charged spherical particles in a salt-free solution are analyzed by using a unit cell model. The linearized Poisson-Boltzmann equation (valid for the cases of relatively low surface charge density or high volume fraction of the particles) and Laplace equation are solved for the equilibrium electric potential profile and its perturbation caused by the imposed electric field, respectively, in the fluid containing the counterions only around the particle, and the ionic continuity equation and modified Stokes equations are solved for the electrochemical potential energy and fluid flow fields, respectively. Explicit analytical formulas for the electrophoretic mobility of the particles and effective electric conductivity of the suspension are obtained, and the particle interaction effects on these transport properties are significant and interesting. The scaled zeta potential, electrophoretic mobility, and effective electric conductivity increase monotonically with an increase in the scaled surface charge density of the particles and in general decrease with an increase in the particle volume fraction, keeping each other parameter unchanged. Under the Debye-Hückel approximation, the dependence of the electrophoretic mobility normalized with the surface charge density on the ratio of the particle radius to the Debye screening length and particle volume fraction in a salt-free suspension is same as that in a salt-containing suspension, but the variation of the effective electric conductivity with the particle volume fraction in a salt-free suspension is found to be quite different from that in a suspension containing added electrolyte.     

Computational examination on monomeric,dimeric, trimeric structural and vibrational interactions,AIM, Hirshfeld,IGM and oxygenated solvent effect on optical properties for pyridine N-oxide

This work reports DFT (Density functional theory) and topological examination by means of AIM (Atom in molecule) theory, Laplacian electron density (ED), Electron –Localization function (ELF) and Hirshfeld surface were executed monomer, dimer and trimer structure of PNO molecule. These structures were optimized and Structural parameters like bond – length and Angles are compared by using B3LYP/6-311G++(d,p) basis set. Computed vibrational – frequencies and corresponding PED (Potential energy – Distribution) were also compared. Polarizability, Dipole moment and the electronic properties were calculated for all three cases of PNO molecule. Hirshfeld surface investigation has been executed to achieve the C–H?O/N–O?H type of hydrogen -bond intermolecular interactions. Moreover, Reactive site, inter/intra interactions are calculated, the optical behaviors for monomer structure of PNO were investigate by using UV–Vis spectroscopy in oxygenated solvents.     

高光学质量氮化碳薄膜的制备和表征

氮化碳(graphitic carbon nitride,g-CN)作为一种非金属半导体材料已被广泛应用于多种能源相关领域研究中。目前由于制备高质量g-CN薄膜的困难,大大限制了其在实际器件上的应用。本文中,我们报道了一种可制备高光学质量gCN薄膜的方法:即由三聚氰胺先通过热聚合制备本体g-CN粉末,再由本体g-CN粉末经过气相沉积在ITO导电玻璃或钠钙玻璃基底上制备g-CN薄膜。扫描电子显微镜和原子力显微镜的测量结果表明在ITO玻璃基底上形成的g-CN薄膜形貌结构均一且致密,厚度约为300nm。扫描电镜能量色散能谱和X射线光电子能谱测量结果表明在ITO玻璃基底上制备的g-CN薄膜的化学组成与本体g-CN粉末的化学组成基本一致。同时,我们发现制备的g-CN薄膜和本体g-CN粉末一样在光照射下可以有效降解亚甲基蓝染料。此外,我们还测量了制备的g-CN薄膜的稳态吸收光谱、稳态荧光光谱、荧光寿命和价带谱,并运用吸收光谱和价带谱数据确定了其能带结构。     

A semi-empirical approach to the modeling of the electrophoretic mobility in free solution: application to polystyrenesulfonates of various sulfonation rates

This work focuses on the understanding of the electrophoretic behavior of flexible chains of polystyrenesulfonates (PSSs) in free solution. It deals mainly with the variation of the electrophoretic mobility with (i) the polymerization degree (N) of fully sulfonated PSSs and (ii) the sulfonation rate of randomly sulfonated PSSs. In both cases, the electrophoretic mobility was modeled following a semi-empirical approach which involves parameters retaining a physical meaning. Fully sulfonated PSS oligomers, having a length smaller than or similar to the Debye length, exhibit a particular electrophoretic behavior, in-between that observed for multicharged small molecules and that for polyelectrolytes. The electrophoretic mobility of these oligomers increases strongly with N, which is attributed to a hydrodynamic coupling between monomers. Then the mobility is maximum for an N of about 10, for which the PSS oligomers are still in a rod-like conformation. Afterwards, as N increases and the PSSs are larger than the Debye length, the electrophoretic mobility decreases slowly until it reaches a constant value corresponding to the free-draining behavior. Next, the electrophoretic behavior of long PSS (N about 1,200) differing in their sulfonation rates was investigated. The effective charge rates were determined independently by conductimetric measurements and the mobilities were modeled as a function of the sulfonation rate. The PSS behavior observed was compared to the one previously reported for classical polyelectrolytes having hydrophilic backbones, such as copolymers of poly(acryamide-coacrylic acid). A specific behavior has been pointed out for these partially sulfonated PSSs, which is attributed to the hydrophobicity of their backbone. Finally, it is shown that separations of PSSs of different sulfonation rates can be obtained with electrolytes containing an anionic surfactant or methanol.     

The reaction of tetrakis(dimethylamido)titanium with self-assembled alkyltrichlorosilane monolayers possessing -OH, -NH2, and -CH3 terminal groups

The reactions of tetrakis(dimethylamido)titanium, Ti[N(CH(3))(2)](4), with alkyltrichlorosilane self-assembled monolayers (SAMs) terminated by -OH, -NH(2), and -CH(3) groups have been investigated with X-ray photoelectron spectroscopy (XPS). For comparison, a chemically oxidized Si surface, which serves as the starting point for formation of the SAMs, has also been investigated. In this work, we examined the kinetics of adsorption, the spatial extent, and stoichiometry of the reaction. Chemically oxidized Si has been found to be the most reactive surface examined here, followed by the -OH, -NH(2), and -CH(3) terminated SAMs, in that order. On all surfaces, the reaction of Ti[N(CH(3))(2)](4) was relatively facile, as evidenced by a rather weak dependence of the initial reaction probability on substrate temperature (T(s) = -50 to 110 degrees C), and adsorption could be described by first-order Langmuirian kinetics. The use of angle-resolved XPS demonstrated clearly that the anomalous reactivity of the -CH(3) terminated SAM could be attributed to reaction of Ti[N(CH(3))(2)](4) at the SAM/SiO(2) interface. Reaction on the -NH(2) terminated SAM proved to be the "cleanest", where essentially all of the reactivity could be associated with the terminal amine group. In this case, we found that approximately one Ti[N(CH(3))(2)](4) adsorbed per two SAM molecules. On all surfaces, there was significant loss of the N(CH(3))(2) ligand, particularly at high substrate temperatures, T(s) = 110 degrees C. These results show for the first time that it is possible to attach a transition metal coordination complex from the vapor phase to a surface with an appropriately functionalized self-assembled monolayer.     

Spontaneous surface flattening via layer-by-layer assembly of interdiffusing polyelectrolyte multilayers

We report a facile means to achieve planarization of nonflat or patterned surfaces by utilizing the layer-by-layer (LbL) assembly of highly diffusive polyelectrolytes. The polyelectrolyte pair of linear polyethylenimine (LPEI) and poly(acrylic acid) (PAA) is known to maintain intrinsic diffusive mobility atop or even inside ionically complexed films prepared by LbL deposition. Under highly hydrated and swollen conditions during the sequential film buildup process, the LbL-assembled film of LPEI/PAA undergoes a topological self-deformation for minimizing surface area to satisfy the minimum-energy state of the surface, which eventually induces surface planarization along with spontaneous filling of surface textures or nonflat structures. This result is clearly different from other cases of applying nondiffusive polyelectrolytes onto patterned surfaces or confined structures, wherein surface roughening or incomplete filling is developed with the LbL assembly. Therefore, the approach proposed in this study can readily allow for surface planarization with the deposition of a relatively thin layer of polyelectrolyte multilayers. In addition, this strategy of planarization was extended to the surface modification of an indium tin oxide (ITO) substrate, where surface smoothing and enhanced optical transmittance were obtained without sacrificing the electronic conductivity. Furthermore, we investigated the potential applicability of surface-treated ITO substrates as photoelectrodes of dye-sensitized solar cells prepared at room temperature. As a result, an enhanced photoconversion efficiency and improved device characteristics were obtained because of the synergistic role of polyelectrolyte deposition in improving the optical properties and acting as a blocking layer to prevent electron recombination with the electrolytes.     

Temperature dependence of the field effect mobility of solution-grown germanium nanowires

The temperature dependence of the field effect mobility was measured for solution-grown single-crystal Ge nanowires. The nanowires were synthesized in hexane from diphenylgermane by the supercritical fluid-liquid-solid process using gold nanocrystals as seeds. The nanowires were chemically treated with isoprene to passivate their surfaces. The electrical properties of individual nanowires were then measured by depositing them on a Si substrate, followed by electrical connection with Pt wires using focused ion beam assisted chemical vapor deposition. The nanowires were positioned over TaN or Au electrodes covered with ZrO2 dielectric that were used as gates to apply external potentials to modulate the conductance. Negative gate potentials increased the Ge nanowire conductance, characteristic of a p-type semiconductor. The temperature-dependent source/drain current-voltage measurements under applied gate potential revealed that the field effect mobility increased with increasing temperature, indicating that the carrier mobility through the nanowire is probably dominated either by a hopping mechanism or by trapped charges in fast surface states.     

Effects of counterion size on the attraction between similarly charged surfaces

Interaction between similarly charged surfaces can be attractive at high electrostatic coupling constants Ξ = l(B)Z(2)/μ(GC), where l(B) is the Bjerrum length, μ(GC) the Gouy-Chapman length, and Z the valency of counterions. While this effect has been studied previously in detail, as a function of surface charge density and valency of the pointlike counterions, much less is known about the effect of counterion size. We apply the Wang-Landau sampling Monte Carlo (MC) simulation method to compute the free energy F as a function of the scaled distance between the plates D?=D/μ(GC) for a range of Ξ and scaled counterion radii R?=R/μ(GC). We find that for large Ξ and small ion radius, there is a global equilibrium distance D?=D?(eq)=2(1+R?), correctly giving the expected value at the point counterion limit. With increasing R? the global minimum in F(D?) changes to a metastable state and finally this minimum vanishes when R? reaches a critical value, which depends on Ξ. We present a state diagram indicating approximate boundaries between these three regimes. The Wang-Landau MC method, as it is applied here, offers a possibility to study a wide spectrum of extended problems, which cannot be treated by the use of contact value theorem.     

氢原子吸附的Cu(100)表面原子结构和电子态

用密度泛函理论的总能计算研究了金属铜(100)面的表面原子结构以及在不同覆盖度时氢原子的吸附状态. 研究结果表明, 在Cu(100)c(2×2)/H表面体系中, 氢原子吸附的位置是在空洞位置, 距最外层Cu原子层的距离为0.052 nm, 相应的Cu—H键长为0.189 nm, 并通过计算结构参数优化否定了其它的吸附位置模型. 总能计算得出Cu(100)c(2×2)/H表面的功函数为4.47 eV, 氢原子在这一体系的吸附能为2.37 eV(以孤立氢原子为能量参考点). 通过与衬底原子的杂化, 氢原子形成了具有二维特征的氢能带结构, 在费米能级以下约0.8 eV处出现的表面局域态是Cu(S)-H-Cu(S-1)型杂化的结果. 采用Cu(100)表面p(1×1)、p(2×2)和p(3×3)的三种氢吸附结构分别模拟1, 1/4, 1/9的原子单层覆盖度, 计算结果表明, 随着覆盖度的增加, 被吸附的氢原子之间的距离变短, 使得它们之间的静电排斥和静电能增大, 从而导致表面吸附能和吸附H原子与最外层Cu原子间垂直距离(ZH-Cu)逐渐减小. 在较低的覆盖度下, 氢原子对Cu(100)表面的影响主要表现为单个原子吸附作用的形式. 通过总能计算还排除了Cu(100)表面(根号2×2根号2)R45°-2H缺列再构吸附模型的可能性.