第一章：红外和Raman光谱介绍 ·什么是红外光谱？什么是Raman光谱 ·红外谱仪和Raman谱仪 ·红外光谱和Raman光谱方法的特点 ·红外光谱和Raman光谱研究的基本问题
第一章：红外和Raman光谱介绍 • 什么是红外光谱？什么是Raman光谱 • 红外谱仪和 Raman谱仪 • 红外光谱和Raman光谱方法的特点 • 红外光谱和Raman光谱研究的基本问题
红外和Raman光谱举例 The shear mode of multilayer graphene The quest for materials capable of realizing the next generation of electronic and photonic devices continues to fuel research on the electronic,optical and vibrational properties of graphene. Few-layer graphene(FLG)flakes with less than ten layers each show a distinctive band structure.Thus,there is an increasing interest in the physics and applications of FLGs.Raman spectroscopy is one of the most useful and versatile tools to probe graphene samples.Here,we uncover the interlayer shear mode of FLGs,ranging from bilayer graphene (BLG) to bulk graphite,and suggest that the corresponding Raman peak measures the interlayer coupling.This peak scales from 43 cm-1 in bulk graphite to ~31cm-1 in BLG.Its low energy makes it sensitive to near-Dirac point quasiparticles.Similar shear modes are expected in all layered materials,providing a direct probe of interlayer interactions. nature materials 2012|D0:10.1038/NMAT3245
红外和Raman光谱举例
a 6 1584 k 1.580 Bulk 8LG 1,576 8LG 7孔G (ne)Ausuaju 7LG 6) 1,572 6LG 6LG A4 5LG 5LG 40 4LG m006、 3LG 36 3LG 2LG 32 2LG 8 -40 -20 0 20 40 15601.600 0 01 020.3 04 0.5 Raman shift (cm) 1/N Figure 2 Raman spectra and fits of the C and G peaks as a function of number of layers.a,S/AS Raman spectra for the C peak spectral region(left)and S Raman spectra for the G peak spectral region (right).b,Peak positions Pos(G)(filled black circles)and Pos(C)(open blue circles),as a function of inverse layer number.The red dash-dotted line is a plot of equation(2),open diamonds are DFT calculations.Vertical dashed lines in a and the horizontal line in b are guides to the eye
Quantum memory:Phonons in diamond crystals Time Write pulse Read pulse Optical phonon Q/2 Diamond lattice G Stokes photon Anti-Stokes photon Through Raman scattering,a'write'laser pulse creates a lower-energy Stokes photon(red)and an optical phonon in the diamond lattice.The optical phonon is a single excitation of a vibration mode in which nearest-neighbour carbon atoms move in opposite directions.A'read'laser pulse then converts this phonon into an anti-Stokes photon(blue). Nature Photonics,6,10 (2012)
Through Raman scattering, a 'write' laser pulse creates a lower-energy Stokes photon (red) and an optical phonon in the diamond lattice. The optical phonon is a single excitation of a vibration mode in which nearest-neighbour carbon atoms move in opposite directions. A 'read' laser pulse then converts this phonon into an anti-Stokes photon (blue). Quantum memory: Phonons in diamond crystals Nature Photonics, 6, 10 (2012)
(a) (b 1370cm1 1503cm1 726cm 320J/cm2 A 11J/cm C-C stretching C=O asymmetric 1503 cm-1 ('n'e) A 11J/cm2 stretching 1726cm-1 1370cm aoueqos A-A 11J/cm2 C-N stretching 1800 1600 400 Wavenumber(cm) C-H bending 955cm-1 1.6 A,320J/cm2 1344,1298cm-1 C-C stretching..... A 320J/cm, C-H bending 6 905cm 1 2 Pentacene DR reversed at~33J/cm A,-A,320J/cm 100200300400500600 1450 1350 950 900 850 LPL Exposure(J/cm') Wavenumber(cm) (a)Polarized IR spectra of the Azo-PI film with a LPL exposure of 320 J=cm2.(b)Polarized IR spectra of the pentacene films on 11 J=cm2 and 320 J=cm2 exposed Azo-PI.(c)LPL exposure dependence of DR(A/A)of the Azo-PI films(1370 cm-1 band)and the pentacene films (905 cm-1 band). (Phys.Rev.Lett.,101,236103(2008)
(a) Polarized IR spectra of the Azo-PI film with a LPL exposure of 320 J=cm 2. (b) Polarized IR spectra of the pentacene films on 11 J=cm 2 and 320 J=cm 2 exposed Azo-PI. (c) LPL exposure dependence of DR (A /A) of the Azo-PI films (1370 cm-1 band) and the pentacene films (905 cm-1 band). (Phys. Rev. Lett., 101, 236103 (2008))