首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 93 毫秒
1.
本文对新兴边缘学科-单分子物理与化学的一些研究进展进行简要综述。在对单分子科学中几类基本实验技术如扫描隧道显微术和光镊技术等作了简要介绍之后,重点评述了单分子实验技术和研究方法在物理、化学、生物和分子电子学等学科领域的应用和影响。基于扫描隧道显微术和电子结构计算,列举了最近几个关于单分子高分辨表征、单分子器件和单分子量子调控等方面的研究实例。最后对单分子物理与化学的发展前景进行了展望。  相似文献   

2.
尤思凡  孙鲁晔  郭静  裘晓辉  江颖 《物理学报》2019,68(1):16802-016802
表面和界面水在自然界、人们的日常生活以及现代科技中无处不在.它在物理、化学、环境学、材料学、生物学、地质学等诸多基础学科和应用领域起到至关重要的作用.因此,表面和界面水的功能与特性的研究,是水基础科学的一项核心任务.然而,由于水分子之间氢键相互作用的复杂性,及其与水-固界面相互作用的竞争,使得表(界)面水对于局域环境的影响非常敏感,往往需要深入到分子层次研究其微观结构和动力学过程.近年来,新型扫描探针技术的发展使得人们可以在单分子甚至亚分子尺度上对表(界)面水展开细致的实空间研究.本文着重介绍几种代表性的扫描探针技术及其在表(界)面水体系中的应用,包括:超高真空扫描隧道显微术、单分子振动谱技术、电化学扫描隧道显微术和非接触式原子力显微术.此外,本文还将对表(界)面水扫描探针技术研究面临的挑战和未来发展方向进行了展望.  相似文献   

3.
表面科学中的单分子研究   总被引:1,自引:0,他引:1  
万立骏  王琛  白春礼 《物理》2001,30(3):138-144
简要介绍了表面科学中单分子研究的主要技术手段、研究现状及其发展趋势,特别介绍了扫描隧道显微术(scanning tunneling microscopy,STM)在此研究领域的重要作用以及所获成果等,内容涉及STM技术的特点,材料的表面结构、表面吸附分子的观察、基体对吸附分子成像的影响以及分子操纵和分子器件的构筑等。  相似文献   

4.
用扫描隧道显微术实现室温下的单电子隧穿效应   总被引:2,自引:0,他引:2  
梁励芬  蒋平 《物理》1994,23(7):420-425
单电子隧穿效应通常只能在低温下实现。最近,采用扫描隧道显微术在纳米尺度的范围内实现了室温单电子隧穿,清晰地观察到了库仑阻塞现象和库仑阶梯特性。这是单电子隧穿研究中的重大进展,将在简要叙术单电子隧穿物理过程的基础上予以介绍。  相似文献   

5.
《物理》1994,(4)
1994年第5期《物理》内容预告  知识和进展液态物理进展概述(陆坤权);一种新的笼形分子M8C12(吴自勤)有机的高分子光子学(彭景翠)半导体超微粒的光电子化学(杨迈之)半导体列阵激光器(程文芹)用扫描隧道显微术实现室温下的单电子隧穿效应(梁励芬等...  相似文献   

6.
单分子科学进展   总被引:4,自引:0,他引:4  
杨金龙  李震宇  侯建国  朱清时 《物理》2000,29(10):579-583
综述了新兴边缘学科--单分子科学的进展。对单分子科学的基本实验技术即扫描探针显微术、荧光技术和光镊技术进行了介绍。结合众多的实例(如:对单原子的直接操纵、直接测量化学键强度、在DNA链上“拔河”、用单个C60分子作放大器等)评述了单分子科学方法在各学科领域的广泛应用,以及单分子科学对它们产生的深远影响。最后对单分子科学的发展前景进行了展望。  相似文献   

7.
彭金波  江颖 《物理》2023,(3):186-195
扫描探针显微镜主要包括扫描隧道显微镜和原子力显微镜,其利用尖锐的针尖逐点扫描样品,可在原子和分子尺度上获取表面的形貌和丰富的物性,改变了人们对物质的研究范式和基础认知。近年来,qPlus型高品质因子力传感器的出现将扫描探针显微镜的分辨率和灵敏度推向了一个新的水平,为化学结构、电荷态、电子态、自旋态等多自由度的精密探测和操控提供了前所未有的机会。文章首先简要介绍原子力显微镜的发展历史和基本工作原理,然后重点描述qPlus型原子力显微镜技术的优势及其在单原子、单分子和低维材料体系中的应用,最后展望该技术的未来发展趋势和潜在应用。  相似文献   

8.
纳米光学和生物单分子探测   总被引:3,自引:0,他引:3  
白永强  刘丹  朱星 《物理》2004,33(12):899-906
纳米光学技术展示了纳米级探测本领,同时生物单分子探测所需要分辨尺度也是纳米数量级的,因此在生物单分子探测过程中,纳米光学发挥了巨大的作用.文章介绍了与生物单分子探测技术相关的纳米光学技术,包括量子近场光学探针技术、近场光学成像技术(包括扫描近场光学显微术及全内反射荧光显微术)和激光光钳测控技术及它们在生物单分子探测上的进展,从而在染色、成像、测控三个方面展示了纳米光学技术在生物方面的应用,并对其未来的发展方向进行了展望.  相似文献   

9.
原子力显微术在原子级分辨表征、化学键识别、探测电荷密度分布等领域都有重要的应用.本文在介绍原子力显微术基本工作原理的基础上,着重介绍其在室温原子操纵、对原子/分子操纵过程的表征、以及绝缘基底上的电荷操纵三个方面的工作进展.主要内容有:1)原子力显微术的成像原理及其对典型分子的化学键分辨表征; 2)原子力显微术在室温下的力学操纵和原子识别能力; 3)用原子力显微术操纵分子表面异构或吸附构型变化并表征该过程中的相互作用力; 4)在绝缘基底上通过原子力显微术对单分子及多分子的电荷操纵.原子力显微术操纵在这些领域内的工作拓展了扫描隧道显微镜在原子/分子操纵方面的工作范围,为理解并精确控制操纵过程及构造纳米尺度器件提供了新的思路.  相似文献   

10.
介绍一种新近发展起来的用于磁性表面磁成像技术———自旋极化扫描隧道显微术。该技术结合了扫描隧道显微术的原子分辨和其他磁成像技术中的自旋灵敏的特点 ,成为人们深入开展纳米磁性领域研究的强有力工具。  相似文献   

11.
张尧  张杨  董振超 《物理学报》2018,67(22):223301-223301
分子尺度上的光电相互作用研究可以为发展未来信息和能源技术提供科学基础.扫描隧道显微镜不仅可以用来观察和操纵纳米世界中的原子和分子,而且其高度局域化的隧穿电流还可以被用来激发隧道结中的分子,使之发光,以研究局域场下的分子光电特性.本文综述了中国科学技术大学单分子光电研究组近期在锌酞菁分子电致发光方面取得的科学进展,包括:1)利用有效的电子脱耦合与纳腔等离激元调控技术,实现了隧穿电子激发下的单个锌酞菁分子的电致荧光,并通过发展相关的光子发射统计测量方法,表征了单个分子在隧穿电子激发下的电致荧光具有单光子发射特性;2)发展了具有亚纳米空间分辨的荧光光谱成像技术,实现了对酞菁分子间相干偶极相互作用特征的实空间观察;3)对分子与纳腔等离激元之间的相干耦合作用进行了亚纳米精度的操控,在单分子水平上观察到了法诺共振和兰姆位移效应.这些研究结果不仅为研发基于有机分子的电泵纳米光源与单光子光源等分子光电器件提供了新的思路,而且为在单分子尺度上研究分子光电特性、分子间能量转移以及场与物质之间的相互作用规律等提供了新的表征方法.  相似文献   

12.
Following the development of the scanning tunneling microscope (STM), the technique has become a very powerful and important tool for the field of surface science, since it provides direct real-space imaging of single atoms, molecules and adsorbate structures on surfaces. From a fundamental perspective, the STM has changed many basic conceptions about surfaces, and paved the way for a markedly better understanding of atomic-scale phenomena on surfaces, in particular in elucidating the importance of local bonding geometries, defects and resolving non-periodic structures and complex co-existing phases. The so-called “surface science approach”, where a complex system is reduced to its basic components and studied under well-controlled conditions, has been used successfully in combination with STM to study various fundamental phenomena relevant to the properties of surfaces in technological applications such as heterogeneous catalysis, tribology, sensors or medical implants. In this tribute edition to Gerhard Ertl, we highlight a few examples from the STM group at the University of Aarhus, where STM studies have revealed the unique role of surface defects for the stability and dispersion of Au nanoclusters on TiO2, the nature of the catalytically active edge sites on MoS2 nanoclusters and the catalytic properties of Au/Ni or Ag/Ni surfaces. Finally, we briefly review how reaction between complex organic molecules can be used to device new methods for self-organisation of molecular surface structures joined by comparatively strong covalent bonds.  相似文献   

13.
The development of a method for exploring the ultrafast transient dynamics in small organized structures with high spatial resolution is expected to be a basis for further advances in current science and technology. Recently, we have developed a new microscopy technique by combining scanning tunneling microscopy (STM) with ultrashort-pulse laser technology, which enables the visualization of ultrafast carrier dynamics even on the single-atomic level. A nonequilibrium carrier distribution is generated using ultrashort laser pulses and its relaxation processes are probed by STM using the optical pump-probe method realized in STM by the pulse-picking technique. In this paper, the fundamentals of the new microscopy technique are overviewed.  相似文献   

14.
扫描隧道显微镜是利用探针尖端与物质表面原子间的不同种类的局域相互作用,来测量表面原子结构和电子结构的显微新技术,它的出现被科学界誉为是表面科学和表面现象分析技术的一次革命。  相似文献   

15.
Scanning tunneling microscopy/spectroscopy (STM/STS), which has been so epoch-making in surface science experiments introduced many challenging problems also to the theory of condensed matter physics. Recent progress in theories of STM/STS contributed to revealing the relation between the atomic structure of the tip and the STM/STS data, and to clarify various strange phenomena observed. The present article reviews various important issues of the fundamentals of STM/STS from theoretical view points.

After surveying the so far presented theoretical approaches, the first-principles simulation method based on the microscopic electronic state of both the sample surface and the tip is introduced. Several examples of the simulation such as graphite and Si surfaces, are described. Some novel phenomena of the microscopic tunnel system of STM such as the negative differential resistance in STS and single electron tunneling through fine supported particles are also discussed, as well as the many-body effect or electron-phonon coupling effect on STM/STS.  相似文献   


16.
Koo TW  Chan S  Berlin AA 《Optics letters》2005,30(9):1024-1026
We report on the applicability of combining surface-enhanced Raman scattering (SERS) with coherent anti-Stokes Raman scattering for high-sensitivity detection of biological molecules. We found that this combination of techniques provides more than 3 orders of signal enhancement compared with SERS and permits monitoring of biological molecules such as deoxyguanosine monophosphate (dGMP) and deoxyadenosine monophosphate at the single-molecule level. This combined technique also improved detection sensitivity for angiotensin peptide. As this is believed to be the first report of detection of dGMP at the single-molecule level, we suggest that this approach can serve as a new tool for biological studies.  相似文献   

17.
The adsorption and reactions of ethylene adsorbed in UHV on Pt(111) have been studied as a function of temperature by STM. The STM images taken at 160K show an ordered structure of adsorbed ethylene. Annealing to 300 K produces ethylidyne (C-CH3) irreversibly, as has been demonstrated by a wide variety of surface science techniques. The ethylidyne on Pt(111) is not visible to the STM at room temperature. Cooling the sample allows direct observation of the ethylidyne ordered structure by STM. Annealing above 430 K results in further dehydrogenation, eventually leaving only carbon on the surface. The decomposition products appear as small clusters which are localized and uniformly distributed over the surface. Further annealing to temperatures >800 K results in the growth of graphite islands on the Pt(111) surface. The annealed graphite islands exhibit several supersturctures with lattice parameters of up to 22 Å, which are thought to result from the higher order commensurability with the Pt(111) substrate at different relative rotations.  相似文献   

18.
用扫描隧道显微镜测量局域功函数   总被引:1,自引:0,他引:1       下载免费PDF全文
用扫描隧道显微镜在Cu(111)-Au和Pt(111)-Ag表面上对局域功函数进行了测量.在扫描的同时通过测量隧道电流对针尖样品间距离变化的响应,可以在得到扫描隧道显微镜(STM)图的同时得到功函数图.用这种方法,成功地观察到Au,Ag覆盖层与Cu,Pt衬底间的功函数的差别.结果表明:Au覆盖层的功函数介于Cu(111)和Au(111)的功函数之间,这与其它方法的结果一致.在Pt(111)-Ag表面观察到了局域功函数随覆盖层厚度的变化.本工作表明:扫描隧道显微镜在研究功函数与表面结构的关系方面是十分有用的;用测量局域功函数的方法还可以区分表面不同种的物质 关键词:  相似文献   

19.
Tunnelling electrons may scatter inelastically with an adsorbate, releasing part of their energy through the excitation of molecular vibrations. The resolution of inelastic processes with a low temperature scanning tunnelling microscope (STM) provides a valuable tool to chemically characterize single adsorbates and their adsorption mechanisms. Here, we present a molecular scale picture of single molecule vibrational chemistry, as resolved by STM. To understand the way a reaction proceed it is needed knowledge about both the excitation and damping of a molecular vibration. The excitation is mediated by the specific coupling between electronic molecular resonances present at the Fermi level and vibrational states of the adsorbate. Thus, the two-dimensional mapping of the inelastic signal with an STM provides the spatial distribution of the adsorbate electronic states (near the Fermi level) which are predominantly coupled to the particular vibrational mode observed. The damping of the vibration follows a competition between different mechanisms, mediated via the creation of electron-hole pairs or via anharmonic coupling between vibrational states. This latter case give rise to effective energy transfer mechanisms which eventually may focus vibrational energy in a specific reaction coordinate. In this single-molecule work-bench, STM provides alternative tools to understand reactivity in the limit of low excitation rate, which demonstrate the existence of state-specific excitation strategies which may lead to selectivity in the product of a reaction.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号