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1.
A plane wave density functional theory method was used to investigate the adsorption properties of isolated alkali metal atoms, including Li, Na, K, Rb and Cs on-top of the F 0 s defective center of MgO(001) surface. Among all the alkali metals, the lithium atom binds most strongly with the highest adsorption energy of 0.67 eV and the shortest distance of about 0.257 nm between metal and the surface, the binding energy for the sodium atom comes second, and just half of this value for the other alkali metal ... 相似文献
2.
Elemental mercury has become a global concern because of its significant impact on human health and the ecosystem. A lot of effort has been put towards the removal of elemental mercury from the 2H-MoS2 (prismatic structure of MoS2). However, the mechanism of 1T-MoS2 (polytype structure of MoS2) in Hg0 capture remains unexplored. In this study, density functional theory (DFT) was adopted to investigate the adsorption mechanism of Hg on a 1T-MoS2 monolayer. The different possible adsorption positions on the 1T-MoS2 were examined. For different adsorption configurations, the changes in electronic property were also studied to understand the adsorption process. The results elucidated that chemisorption dominates the adsorption between Hg0 atoms and the 1T-MoS2. It was found that the TMo (on top of the Mo atom) position is the strongest adsorption configuration among all the possible adsorption positions. The adsorption of Hg0 atoms on the 1T-MoS2 monolayer is influenced by adjacent S and Mo atoms. The adsorbate Hg0 atom is found being oxidized on the TMo position of the 1T-MoS2 with an adsorption energy of ?1.091 eV. From the partial density of states (PDOS) analysis of the atoms, the strong interaction between Hg0 and the 1T-MoS2 surface is caused by the significant overlap among the d orbitals of the mercury atom and the s orbital of the S atom and p and d orbitals of the Mo atom. 相似文献
3.
Liu He Cheng Xinbing Zhang Rui Shi Peng Shen Xin Chen Xiaoru Li Tao Huang Jiaqi Zhang Qiang 《天津大学学报(英文版)》2020,26(2):127-134
Lithium(Li) metal anode has received extensive attentions due to its ultrahigh theoretical capacity and the most negative electrode potential. However, dendrite growth severely impedes the practical applications of the Li metal anode in rechargeable batteries. In this contribution, a mesoporous graphene with a high specific surface area was synthesized to host the Li metal anode. The mesoporous graphene host(MGH) has a high specific surface area(2090 m~2/g), which affords free space and an interconnected conductive pathway for Li plating and stripping, thus alleviating the volume variation and reducing the generation of dead Li during repeated cycles. More importantly, the high specific surface area of MGH efficiently reduces the local current density of the electrode, which favors a uniform Li nucleation and plating behavior, rendering a dendritefree deposition morphology at a low overpotential. These factors synergistically boost the Li utilization(90.1% vs. 70.1% for Cu foil) and life span(150 cycles vs. 100 cycles for Cu foil) with a low polarization of MGH electrode at an ultrahigh current of 15.0 m A/cm~2. The as-prepared MGH can provide fresh insights into the electrode design of the Li metal anode operating at high rates. 相似文献
4.
采用密度泛函计算方法结合周期性平板模型进行结构优化,系统研究了H、O、N、S和C原子在Au(111)表面的吸附能、稳定吸附位点、吸附结构及扩散能垒等信息.现有计算结果如下:C、S、O、N和H原子的最稳定吸附位置均为Fcc空位,吸附能由弱到强的顺序为H相似文献
5.
应用自旋极化的第一性原理对在Mo（110）衬底上生长Fe薄膜进行系统研究．计算结果表明：紧邻界面的Mo原子层向外驰豫,而Fe原子层则表现向内驰豫．Fe／Mo（110）系统的键合表现为各向异性,在平行于Mo（110）表面方向,各个原子之间都表现为金属键,而在垂至于Mo（110）表面方向,Fe原子之间、Fe原子和Mo原子之间却表现为金属键．Fe／Mo薄膜中,Fe原子的磁矩大于体材料Fe原子的磁矩,以铁磁方式排列,并且在紧邻界面的Mo原子诱导出少量的磁矩,这些磁矩与Fe原子以反铁磁的方式排列． 相似文献
6.
从第一性原理出发,采用密度泛函理论（DFF）的杂化密度泛函B3LYP方法,在6—31G（d）全电子基组水平上对Mg6B14笼状结构团簇进行了结构优化和频率分析,同时对团簇的能隙、结合能等电子性质进行了分析,用自然键轨道（NaturalBondOrbital,NBO）方法分析了团簇的电荷布局特性和成键性质。结果表明,电荷从Mg原子上转移到B原子上,主要是位于环上的B原子之间成键。B原子主要是sp杂化形成的π键、大π键,Mg原子主要是S轨道参与成键。 相似文献
7.
利用Xα方法研究了氧化物La2-yBayCuO4的电子结构．研究结果显示,Ba掺杂对氧化物La2-yBayCuO4的电子态密度分布和能带结构有重要影响：（1）掺杂使由原来导电类型相反的两个基元组成的反铁磁绝缘体La2-yBayCuO4,变成了由导电类型相同的两个基元组成的超导体La2-yBayCuO4（2）掺杂使能带显著展宽,使电子态密度在Fermi面附近显著增大,并且d电子的贡献成为主要成分,而S电子的贡献却很小．说明高温超导主要是d波配对机制,S波配对是次要的,自旋涨落交换耦合可能是产生d波配对的主要原因．（3）Ba掺杂使Ba的电负性增强,O的电负性减弱,使La—O层、Cu—O层中的离子键、共价键特征演变成金属键特征,且使原团簇La8CuO6中Cu—O层由原来的接受电子特征变成提供电子的特征． 相似文献
8.
运用玻尔理论及受力分析的方法,考虑相互作用的不同情况,分析了氢原子与碱金属原子能级结构,并进行了数值计算,画出了能级结构图.再运用比较研究的方法对氢原子能级与碱金属原子能级进行比较,找出其相同点及不同点. 相似文献
9.
《天津大学学报(英文版)》2020,(4)
FePS_3, a classical 2D layered material with transition metal phosphorous trichalcogenides, was investigated as an anode material for Mg ion batteries. We used density functional theory to calculate the Mg storage properties of FePS_3, such as Mg adsorption energy, theoretical specifi c capacity, average voltage, diff usion energy barriers, volume change, and electronic conductivity. The theoretical specifi c capacity of the FePS_3 monolayer is 585.6 mA h/g with a relatively low average voltage of 0.483 V(vs. Mg/Mg~(2+)), which is favorable to a high energy density. The slight change in volume and good electronic conductivity of bulk FePS 3 are benefi cial to electrode stability during cycling. 相似文献
10.
研究了电场中的高里德堡态锂原子的动力学特征．由于原子实的存在,即使是能量很低时锂原子的哈密顿量也不能分离变量,因此在核区附近总是存在着混沌．利用Poincaré截面的方法比较了锂原子与氢原子在动力学性质方面的不同,并进一步说明在外场中非氢里德堡原子的光吸收回归谱中所出现新的共振峰可以归结为原子实的散射作用产生的组合轨道的效应． 相似文献
11.
采用第一原理研究了Au在ZnO两个极性表面（0001）-Zn和（0001）-O的吸附,分析了单层Au吸附在ZnO极性表面上的态密度和吸附构型.计算结果表明：ZnO极性表面上单层Au吸附层能提高Zn原子在（0001）-Zn和（0001）-O面上的吸附能分别0.41 eV/原子和0.42 eV/原子;同时Au吸附层又比Zn吸附层更加活跃,总能计算可以看出Au处于顶端的构型比Au扩散构型更加稳定,使得Au恒处于顶端,很好的解释了Au在ZnO纳米结构生长过程中充当表面活性剂的角色.理论计算与实验中发现Au颗粒总是在生长出的纳米结构的末端这一现象吻合很好. 相似文献
12.
从多铁材料出发,介绍了三角反铁磁多铁材料ACrO2（A=Li,Na,K,Ag或Cu）的最新研究进展．这类多铁材料的磁性和铁电性存在很强的耦合和相互调控效应,铁电性来源于非共线螺旋自旋序,具有丰富的物理内涵,在自旋电子学等领域有着广阔的应用前景．基于密度泛函理论（DFT）的投影扩充波（PAW）方法,在广义梯度近似（GGA）下,对AgCrO2的磁结构和磁电性质进行了研究．共线磁结构计算结果表明,AgCrO2材料具有条纹反铁磁基态．态密度分析显示,Cr^3＋对体系的物理性质起决定性作用．通过非共线磁性结构计算,分别给出了平行于（110）而（11^-0）面内120°自旋构型．AgCrO2与（11^-0）具有很强的层内耦合作用,而层间耦合作用非常微弱,是典型二维三角格子Heisenberg材料． 相似文献
13.
任玲 《昆明师范高等专科学校学报》2011,(6):96-99
基于密度泛函理论,用第一性原理计算研究了氯原子在氧化铟半导体表面的吸附作用．结果表明,经过氯原子吸附后的氧化铟表面功函数随着氯原子覆盖度的增大而线性地增大．电子局域态密度及电荷转移分析发现,氯原子吸附能够饱和氧化铟表面悬挂键,使得表面铟原子的电荷转移到氯原子上,在氧化铟表面形成一层电偶极子．表面电偶极子的形成导致氯吸附的氧化铟表面势能被抬高,从而提高了其表面功函数． 相似文献
14.
应用群论基本原理讨论了AO4^n-中中心原子A的可能杂化方式，结合A在周期表中的位置以及能量近似原理和能量最低原理确定A采取的杂化方式． 相似文献
15.
房丽敏 《广东教育学院学报》2010,(5):62-66
采用在密度泛函理论框架下的第一性原理方法,系统地分析了4种可能Au/SrTiO3（001）界面模型的界面能、原子间距、电子结构及其化学键特征.研究表明：Au/SrTiO3（001）界面的稳定性与其界面原子构型密切相关;Au与排列在以TiO2原子层截止SrTiO3（001）表面的氧原子上的界面构型最为稳定. 相似文献
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17.
采用基于周期性密度泛函理论的第一性原理,文章计算了N吸附于锐钛矿2TiO 晶体表面和掺杂于2TiO （001）的表面及次表面后晶体结构的变化及形成能,并讨论了能带结构及态密度的变化。通过形成能的比较发现, N最佳掺杂位为2TiO （001）表面空穴位,且掺杂后在2TiO 表面形成新的成键结构。通过对能带的观测可以发现由于N的掺杂使得2TiO 出现明显的半金属性。 相似文献
18.
Thetechnologyofcoldpressureweldingiswidelyusedtoachievethejoiningofthesameordifferentmetalswithdif ferentthermal physicspropertiesandotherconditions ,foritsparesenergysources ,simplifiestheweldingequipment,anditdoesnotneedtobeheatedanddoesnotcausethemeltingandtheheateffectzone ,brittlecompounds .Accordinglythetechnologymaybesatisfyingwithdemandforcomprehensivepropertiesinindustry ,andwillsettletheconflictbetweentheincreasingdeficienciesandgrowingdemands .Onthesideofmetallurgicability[1] ,thewe… 相似文献
19.
A new oxadiazole-functionalized polyacrylonitrile fiber(PAN_(AO)F) was successfully fabricated by immobilizing the organic molecule 2-chloromethyl-5-phenyl-1,3,4-oxadiazole on aminated fiber(PAN_AF).The fibers were characterized completely by Fourier-transform infrared spectroscopy,elemental analysis,X-ray diffraction,and X-ray photoelectron spectroscopy techniques.Compared with PAN_AF,PAN_(AO)F showed a higher adsorption capability for Hg~(2+) ions in aqueous solutions.The functionalized fiber PAN_(AO)F exhibited a highly selective adsorption for Hg~(2+) when coexisting with other metal ions viz.Pb~(2+),Cd~(2+),Cu~(2+),Zn~(2+),Ni~(2+),Co~(2+),Cr~(3+),Ca~(2+),and Mg~(2+).The PAN_(AO)F presented the best adsorption capacity for Hg~(2+)at pH 5.Moreover,the adsorption experimental data fit well with the pseudo-second-order kinetic model and Langmuir isotherm.Notably,the PAN_(AO)F almost retained its original adsorption capacity(112 mg/g) after five cycles,indicating its excellent reusability in practical applications. 相似文献
20.
基于周期性密度泛函理论,本文研究了Fe吸附于锐钛矿TiO2（001）面、替位掺杂表面Ti位,以及在横向晶隙和纵向晶隙内部掺杂的晶体结构变化及形成能,讨论了对应的能带结构及态密度的变化。为与表面氧空位进行对比,计算了氧空位存在条件下的能带结构及态密度。通过形成能的比较发现：Fe在吸附于晶体表面并向体内迁移时,倾向于掺杂在晶体表面晶隙位置。通过对电子结构及态密度的分析发现：Fe在晶体表面晶隙掺杂较表面氧空位掺杂更有利于TiO2光催化氧化效率的提高。 相似文献