Raman光谱(拉曼光谱)第四章4-2-左健-理化中心.ppt

《Raman光谱(拉曼光谱)第四章4-2-左健-理化中心.ppt》由会员分享，可在线阅读，更多相关《Raman光谱(拉曼光谱)第四章4-2-左健-理化中心.ppt（28页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、Raman spectroscopy: high characteristic good spatial resolution (micro Raman) minimal sample preparation all solvents can be usedbut: biological samples often show high fluorescence biological molecules appear often at low concentration levelessential oil10 mmRamansilver colloidsM. x piperita514.5 n

2、m200015001000500Wavenumber / cm-1Raman Intensity 10-8 M10-7 M10-6 M10-5 M10-3 M10-2 M10-1 M15001000500Raman IntensityRamanWavenumber / cm-115001000500Wavenumber / cm-1 Raman IntensitySERS NHNNNNH2EOmetal colloidexcitationdetectionSERSmoleculeSERS: Excitation of plasmon resonances in Ag (Au or Cu) na

3、noparticlesRaman spectroscopy utilizes optical properties of nanostructuresWavelength nmSCS nmJ. Kottmann et al., IFH Field Theory Group,ETH ZrichAg, Au or Cu Wavelength/nmScattering Cross sectionFieldenhancementSERS: Raman spectroscopy utilizes optical properties of nanostructuresJ. Kottmann et al.

4、, IFH Field Theory Group,ETH ZrichWavelength nmSCS nm*10Scattering Cross sectionWavelength/nmFieldenhancementSERS: Raman spectroscopy utilizes optical properties of nanostructures20 nmJ. Kottmann et al., IFH Field Theory Group,ETH ZrichAg, Au or Cu Fieldenhancement4002001005020105210.50.2Scattering

5、Cross sectionWavelength/nmTypical SERS media 不同形状金纳米粒子的表面增强拉曼光谱 自组装好的不同形状的金纳米粒子的硅片浸没在20mM NaSCn 的溶液里,取出后测量其SERS信号以以SCN - 作为探针分子作为探针分子,绿光绿光(51415nm) 作为作为激发光波长得到的激发光波长得到的SERS谱图谱图具有较高SERS 活性的粗糙铂电极的STM (a) 和镍纳米线阵列的A FM (b) 图像各种过渡金属表面上吸附的吡啶在最强峰各种过渡金属表面上吸附的吡啶在最强峰电位下的表面增强拉曼谱图电位下的表面增强拉曼谱图Rayleigh LimitNear-

6、field resolutionL. Novotny and C. Hafner, Phys. Rev. E 50 (1994).AluminumHE11250 nm160 nm pulled etched/old etched/newTransmission:0.0001%0.1%Stckle et al., Appl. Phys. Lett. 75, 161 (1999) Raman intensity of water stretching vibration vs. the distance covered by the piezo translator Raman spectral

7、shift of water stretching vibration vs the distance covered by the piezo translatorHeterogeneous CatalysisHeterogenous CatalysisCorrelation of Topography and Spectra500 nmTopography + 3 H2?PdC. Fokas and V. Deckert, Appl. Spectrosc. 56, 192 (2002)SampleSingle SERS active particleAFM cantileverIllumination/ collection opticsR. Stckle, Y. D. Suh, V. Deckert, R. Zenobi, Chem. Phys. Lett., 2000, 318, 131.