Studies on Near-field Coupling Effects of Metal Nanoparticles and Applications of Discrete Dipole Approximation

金属纳米粒子间的近场耦合效应对其远场光学和近场分布都有着巨大影响，它是形成表面增强拉曼散射（SERS）的增强“热点”的关键因素。本论文的中心工作是从理论上定量研究球形及非球形金属纳米粒子二聚体的线性光学性质和它们在SERS应用中的电磁场增强机理。 本文首先利用广义米氏散射理论（GeneralizedMie）系统研究了球形钯、银等纳米粒子二聚体的线性光学性质及其SERS增强效应。计算表明，粒子间的近场耦合效应对粒子对的吸收、散射和消光光谱影响显著，表面等离子体激元共振峰的位置随粒子间隔的变小而显著红移。在耦合效应和尺寸效应的共同作用下，钯纳米粒子二聚体的表面平均SERS增强因子可达105～10...The near-field coupling effect of metal nanoparticles has great influence on the far field spectra and the near field distributions, particularly on the enhanced ‘hot spot’ for the surface-enhanced Raman scattering (SERS). The main focus of this thesis is to theoretically study the quantitative dependence of the linear optical properties and electromagnetic (EM) enhancement mechanism. The linear ...学位：理学硕士院系专业：物理与机电工程学院物理学系_光学学号：1982007115230

钯纳米粒子体系中的近场耦合与SERS效应

利用广义米氏散射理论(gEnErAlIzEd MIE)从理论上系统研究了球形钯纳米粒子二聚体的线性光学性质及其表面增强拉曼散射效应.计算表明,粒子间的近场耦合效应对粒子对的吸收、散射和消光光谱影响显著,其表面等离子体激元共振峰的位置随粒子间隔的变小而显著红移.在耦合效应和尺寸效应的共同作用下,钯纳米粒子二聚体中“热点“位的最大SErS增强因子可达到107~108,表面平均SErS增强因子可达105~106.通过对远场和近场的对比研究,发现消光谱与粒子间的近场增强谱的谱型大致相同,但消光谱的极值峰位与SErS的最大增强峰位之间存在一定的偏离,这显示了表面等离子激元共振对远场和近场的不同影响,我们对此进行了讨论.相关结果对揭示远场与近场的关联性及探索过渡金属体系中表面增强散射的电磁场增强机理有较重要的科学意义.国家自然科学基金(20703032);国家重点基础研究发展计划(2009CB930703);福建省自然科学基金(E0710028)资助项

Freestanding palladium nanosheets with plasmonic and catalytic properties

通讯作者地址: Huang, XQ (通讯作者), Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surfaces, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 3. Xiamen Univ, Dept Phys, Xiamen 361005, Peoples R China 电子邮件地址: [email protected] metal films can exhibit quantum size and surface effects that give rise to unique physical and chemical properties(1-7). Metal films containing just a few layers of atoms can be fabricated on substrates using deposition techniques(7), but the production of freestanding ultrathin structures remains a significant challenge. Here we report the facile synthesis of freestanding hexagonal palladium nanosheets that are less than 10 atomic layers thick, using carbon monoxide as a surface confining agent. The as-prepared nanosheets are blue in colour and exhibit a well-defined but tunable surface plasmon resonance peak in the near-infrared region. The combination of photothermal stability and biocompatibility makes palladium nanosheets promising candidates for photothermal therapy. The nanosheets also exhibit electrocatalytic activity for the oxidation of formic acid that is 2.5 times greater than that of commercial palladium black catalyst.NSF of China 20925103 20871100 20721001 20703032 MOST of China 2009CB930703 2011CB932403 Fok Ying Tung Education Foundation 121011 NSF of Fujian 2009J06005 Key Scientific Project of Fujian Province 2009HZ0002-

Ar~(16+)与Zr作用产生的X射线谱

本工作对超导离子源(SECRAL)上的10~20 kV/q Ar16+和Ar17+入射到金属Zr表面进行实验研究。实验结果表明,高电荷态Ar16+在金属表面存在着多电子激发过程。Ar空心原子的K层发射X射线强度随入射离子的动能减少,靶原子Zr的L壳层发射X射线强度随入射离子动能的增加而增强。Ar17+单离子的K-αX射线产额比Ar16+单离子的K-αX射线产额大5个数量级

84.5MeV~(12)C~(4+)离子诱发金属靶原子发射的Kβ与Kα-X射线强度比值的研究

本实验是在中国科学院兰州近代物理研究所,国家实验室的重离子加速器上完成的.实验用OR-TEC公司生产的HPGe X射线探测器测量了84.5 MeV的12C4+离子轰击Cu,Mo,Ag,Cd,In,Sn,W和Au金属靶产生的K壳层特征X射线谱,计算了Kβ与Kα-X射线强度的比值,并将结果与Scofield用Hartree-Fock-Slater模型计算出的理论值与用其它方法(如:衰变幅射,用光子,电子,质子等粒子与靶相互作用)得到的实验值进行了比较.比较结果表明用84.5 MeV的12C4+离子轰击Cu,Mo,Ag,Cd,In,Sn,W和Au金属靶产生的Kβ与K-αX射线强度比值比理论值和其它实验值要大许多

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies