Rh(111)表面NO分子对多层膜的原子结构  

Structure of NO dimer multilayer on Rh(111)

作　　者：汪辰超 吴太权[1] 王新燕[1] 江影[1] Wang Chen-Chao Wu Tai-Quan Wang Xin-Yan Jiang Ying(Department of Applied Physics, China Jiliang University, Hangzhou 310018, China)

机构地区：[1]中国计量大学应用物理系,杭州310018

出　　处：《物理学报》2017年第2期298-306,共9页Acta Physica Sinica

基　　金：浙江省自然科学基金(批准号:LY13E080007)资助的课题~~

摘　　要：利用第一性原理研究了NO分子对[(NO)_2]分子链、分子单层膜,Rh(111)表面上的(NO)_2分子单层膜和多层膜的原子结构.(NO)_2分子单体在虚拟Rh(111)表面自组装成两个稳定的分子链,(NO)_2分子平行有序排列,氧原子和氮原子都呈现(100)和(111)结构.在虚拟Rh(111)-(1×3^(1/2))上,1.00 ML(molecular layer)覆盖度时,(NO)_2分子自组装成两个稳定的分子单层膜(M1和M2),分子膜M1中N-N键与衬底的夹角为70°-90°;分子膜M2中N-N键平行衬底.在M2/Rh(111)中,(NO)_2分子可吸附于顶位、fcc空心位和hcp空心位,通过电荷转移可解释两个空心位的稳定性强于顶位.Rh(111)表面(NO)_2分子多层膜系统中,(NO)_2分子垂直吸附于两个空心位,第一层是分子膜M2,N-N键平行于衬底,第二层及以上都是分子膜M1,N-N键与衬底夹角为70°-90°,分子膜真空层为0.31 nm±0.02 nm.Molecular self-assembly is the spontaneous organization of molecules under thermodynamic equilibrium conditions into well-defined arrangements via cooperative effects between chemical bonds and weak noncovalent interactions.Molecules undergo self-association without external instruction to form hierarchical structures.Molecular self-assembly is ubiquitous in nature and has recently emerged as a new strategy in chemical biosynthesis,polymer science and engineering.NO monomer is apt to be absorbed on the surfaces of some metals such as Ir（111）,Ni（111）,Pd（111）,Pt（111）,Rh（111） and Au（111）,and the interactions of NO monomer with the metal surfaces have been extensively studied.When NO monomer is weakly adsorbed on the noble-metal surface,it cannot be reduced completely but forms a stable structure,which is named NO dimer.The first-principle technique is employed to determine the structures of NO dimer（（NO）2）molecular chains and monolayers on virtual Rh（111）,as well as（NO）2 monolayer and multilayer on Rh（111）.First,（NO）2 monomers are assembled into two stable molecular chains on the virtual Rh（111） surface,whose bind energies are0.309 and 0.266 eV,respectively.The molecular chains are self-assembly systems,in which（NO）2 monomers are parallel and ordered,and the O atoms and N atoms are shown to be of（100） and（111） structures,respectively.Then,the two molecular chains are assembled into two stable monolayers（denoted as M1 and M2） on the virtual Rh（111）-（1×31/3）,and the coverage is 1.00 ML.In the M1 monolayer,the angle between the N N bond of（NO）2monomer and the substrate is in a range of 70° 90°,and in the M2 monolayer,the N N bond is parallel to the substrate.In the adsorption system of M2/Rh（111）,（NO）2 molecules can be adsorbed on the top as well as the hep and fcc hollow sites.When（NO）2 molecules are adsorbed on the top site,the adsorption system is best described by the electron structure Rh＋0.14 N°= O-0.14,and when（NO

关 键 词：一氧化氮分子对 单层膜 多层膜 自组装 

分 类 号：O561[理学—原子与分子物理]