拉曼光譜分析法-課件

拉曼光譜分析法拉曼光譜分析法1RemoteRamanAnalysis

onPlanetaryMissionsToallowRamanspectroscopyatrangeof10'sofmeters.ThisNASA-fundedprojectisaimedatMarslandersorlandersonotherplanets,butalsohasterrestrialuses.RemoteRamanAnalysis

onPlan2激光拉曼光譜基本原理Rayleigh散射：彈性碰撞；無能量交換，僅改變方向；Raman散射：非彈性碰撞；方向改變且有能量交換；Rayleigh散射Raman散射E0基態(tài)，E1振動激發(fā)態(tài)；E0+h0，

E1+h0激發(fā)虛態(tài)；獲得能量后，躍遷到激發(fā)虛態(tài).（1928年印度物理學(xué)家RamanCV發(fā)現(xiàn)；1960年快速發(fā)展）

h

E0E1V=1V=0h0h0h0h0+

E1+h0E0+h0h(0-

)激發(fā)虛態(tài)激光拉曼光譜基本原理Rayleigh散射：Rayleigh散3基本原理1.Raman散射Raman散射的兩種躍遷能量差：

E=h(0-

)產(chǎn)生stokes線；強(qiáng)；基態(tài)分子多；

E=h(0+

)產(chǎn)生反stokes線；弱；Raman位移：Raman散射光與入射光頻率差；ANTI-STOKES0-

RayleighSTOKES0+

0h(0+

)E0E1V=1V=0E1+h0E2+h0

h

h0h(0-

)基本原理1.Raman散射ANTI-STOKES0-4Rayleigh/RamanTransitionsIRAbsorptionsRayleigh/RamanTransitionsIR5Rayleigh/RamanTransitionsandSpectraRayleigh/RamanTransitionsa6Rayleigh/RamanTransitionsandSpectraRayleigh/RamanTransitionsa7TheSpectrumAcompleteRamanspectrumconsistsof:?aRayleighscatteredpeak(highintensity,samewavelengthasexcitation)?aseriesofStokes-shiftedpeaks(lowintensity,longerwavelength)?aseriesofanti-Stokesshiftedpeaks(stilllowerintensity,shorterwavelength)?spectrumindependentofexcitationwavelength(488,632.8,or1064nm)SpectrumofCCl4,usinganAr+laserat488nm.TheSpectrumAcompleteRamans8RamanSpectroscopyAnotherspectroscopictechniquewhichprobestherovibrationalstructureofmolecules.C.V.Ramandiscoveredin1928;receivedNobelPrizein1931.Canprobegases,liquids,andsolids.Mustusealasersourceforexcitation.Resurgenceinrecentyearsduetothedevelopmentofnewdetectorswithimprovedsensitivity.ShiftbackawayfromFT-RamantodispersiveRamanwithmultichanneldetectorsystems.RamanSpectroscopyAnotherspec9InfraredandRamanSpectraofBenzeneIRRamanInfraredandRamanSpectraof10拉曼光譜與紅外光譜分析方法比較拉曼光譜與紅外光譜分析方法比較11SomeRamanAdvantagesHerearesomereasonswhysomeonewouldprefertouseRamanSpectroscopy.?Non-destructivetosamples(minimalsampleprep)?Highertemperaturestudiespossible(don’tcareaboutIRradiation)?Easilyexaminelowwavenumberregion:100cm-1readilyachieved.?Bettermicroscopy;usingvisiblelightsocanfocusmoretightly.?Easysampleprep:waterisanexcellentsolventforRaman.Canprobesamplethroughtransparentcontainers(glassorplasticbag).SomeRamanAdvantagesHereare12WatchforFluorescenceSpectrumofanthracene.A:usingAr+laserat514.5nm.B:usingNd:YAGlaserat1064nm.Wanttouseshortwavelengthbecausescatteringdependson4thpoweroffrequency.…BUT…Wanttouselongwavelengthtominimizechanceofinducingfluorescence.WatchforFluorescenceSpectrum13紅外活性和拉曼活性振動①紅外活性振動

ⅰ永久偶極矩；極性基團(tuán)；ⅱ瞬間偶極矩；非對稱分子；紅外活性振動—伴有偶極矩變化的振動可以產(chǎn)生紅外吸收譜帶.②拉曼活性振動

誘導(dǎo)偶極矩=E非極性基團(tuán)，對稱分子；拉曼活性振動—伴隨有極化率變化的振動。對稱分子：對稱振動→拉曼活性。不對稱振動→紅外活性

Eeer紅外活性和拉曼活性振動①紅外活性振動紅外活性振動—伴有偶極矩14SelectionRuleforRamanScatteringMustbechangeinpolarizabilityNon-PolargroupssuchasC-S,S-S,C=C,CC(triplebond),N=Nandheavyatoms(I,Br,Hg)strongscatterersSymmetricstretchingvibrationsaremuchstrongerscatterersthanasymmetricstretchingvibrationsSelectionRuleforRamanScatt15PolarizationEffectsPolarizationEffects16對稱中心分子CO2，CS2等，選律不相容。無對稱中心分子（例如SO2等），三種振動既是紅外活性振動，又是拉曼活性振動。選律1234拉曼活性紅外活性紅外活性振動自由度：3N-4=4拉曼光譜—源于極化率變化紅外光譜—源于偶極矩變化對稱中心分子CO2，CS2等，選律不相容。選17PolarizationofCCl4

PolarizationofCCl418PolarizationofCHCl3

PolarizationofCHCl319Raman位移

對不同物質(zhì)：不同；對同一物質(zhì)：與入射光頻率無關(guān)；表征分子振-轉(zhuǎn)能級的特征物理量；定性與結(jié)構(gòu)分析的依據(jù)；Raman散射的產(chǎn)生：光電場E中，分子產(chǎn)生誘導(dǎo)偶極距=E

分子極化率；Raman位移對不同物質(zhì)：不同；20由拉曼光譜可以獲得有機(jī)化合物的各種結(jié)構(gòu)信息：2）紅外光譜中，由CN，C=S，S-H伸縮振動產(chǎn)生的譜帶一般較弱或強(qiáng)度可變，而在拉曼光譜中則是強(qiáng)譜帶。3）環(huán)狀化合物的對稱呼吸振動常常是最強(qiáng)的拉曼譜帶。1）同種分子的非極性鍵S-S，C=C，N=N，CC產(chǎn)生強(qiáng)拉曼譜帶，隨單鍵雙鍵三鍵譜帶強(qiáng)度增加。拉曼光譜與有機(jī)結(jié)構(gòu)由拉曼光譜可以獲得有機(jī)化合物的各種結(jié)構(gòu)信息：2）紅外光譜中，214）在拉曼光譜中，X=Y=Z，C=N=C，O=C=O-這類鍵的對稱伸縮振動是強(qiáng)譜帶，反這類鍵的對稱伸縮振動是弱譜帶。紅外光譜與此相反。5）C-C伸縮振動在拉曼光譜中是強(qiáng)譜帶。6）醇和烷烴的拉曼光譜是相似的：I.C-O鍵與C-C鍵的力常數(shù)或鍵的強(qiáng)度沒有很大差別。II.羥基和甲基的質(zhì)量僅相差2單位。III.與C-H和N-H譜帶比較，O-H拉曼譜帶較弱。4）在拉曼光譜中，X=Y=Z，C=N=C，O=C=O-這類鍵22紅外與拉曼譜圖對比紅外光譜：基團(tuán)；拉曼光譜：分子骨架測定；紅外與拉曼譜圖對比紅外光譜：基團(tuán)；23紅外與拉曼譜圖對比紅外與拉曼譜圖對比24RamanandInfraredSpectraofH-C≡C-HAsymmetricC-HStretchSymmetricC-HStretchC≡CStretchRamanandInfraredSpectraof25Vibrationalmodesofmethane(CCl4)Infraredinactive,RamanactivevibrationsInfraredactive,Ramaninactivevibrations314cm-1776cm-1463cm-1219cm-1Vibrationalmodesofmethane(26InfraredandRamanSpectrumofCCl4776cm-1314cm-1463cm-1219cm-1InfraredspectrumRamanspectrumInfraredandRamanSpectrumof272941，2927cm-1

ASCH22854cm-1

SCH21029cm-1

（C-C）803cm-1環(huán)呼吸

1444，1267cm-1

CH22941，2927cm-1ASCH22854cm-1283060cm-1r-H)1600,1587cm-1c=c)苯環(huán)1000cm-1環(huán)呼吸787cm-1環(huán)變形1039,1022cm-1單取代3060cm-1r-H)1600,1587cm-129RamanSpectroscopyRelativelysimpleandnon-destructivestructureanalysistechniqueofcarbonmaterialsPowerfultoolforthestructuralcharacterizationofdiamondoramorphouscarbonmaterials.DLCDiamondRamanSpectroscopyRelativelys30RemoteRamanAnalysis

onPlanetaryMissionsToallowRamanspectroscopyatrangeof10'sofmeters.ThisNASA-fundedprojectisaimedatMarslandersorlandersonotherplanets,butalsohasterrestrialuses.RemoteRamanAnalysis

onPlan31NSOMRamanImagingSpectrumofpotassiumtitanylphosphate.FromHansHallenatNCSU.Squaresare5x5μmsquareofthismaterialdopedwithRb.Anear-fieldscanningmicroscopewasusedandtheRamansignalwasusedtokeythesubstrateresponse.NSOMRamanImagingSpectrumof32ChemicalMappingFocuslasertosmallspot.TunespectrometertoparticularRamantransitionpeak.Rasterscanthesampleunderthelaserbeam,recordintensitychanges.Resultantmapcorrelateswithsubstance.Acquireanentirespectrumateverypoint,thenchoosethefeaturewithwhichtokeytheimage.MotorizedstagefromRenishawforchemicalmapping.Thisisadrugtablet.Theyellowcorrespondstotheactiveingredient.Particlesareinthe10’sofμmrange.ChemicalMappingFocuslaserto33ChemicalImagingNowdefocusthelaser(notasmallspotbutrather“baths”thesampleinlaserradiation).Passtheemittedradiationthroughanarrowbandpassfilter,adjustedtoaparticularwavelength,chosentobeacertainRamanband.FocusthislightontheCCDcamera.BrightregionscorrespondtolocationsofsubstancegivingrisetoRamansignal.Mixtureofcocaineandsugar.Brightspotsarecocaine.ChemicalImagingNowdefocusth34Applications-ArtRestorationThis12centuryfrescoonachurchwallinItalyneededtoberestored.Whatpaintstouse?Ramananalysisclearlyidentifiedthepaintsandpigmentsthatwereoriginallypresent,permittingacorrectchoiceofcleaningmaterialsandsubsequentrepaintingtorestoreitsoriginalcondition.Applications-ArtRestoration35Applications-PaintChipsForensicanalysisofpaintchipsinvehicleaccidents.Oftenmultiplelayers.CananalyzewithIRbystrippingsuccessivelayers.ImageedgewithmicroRaman.Layers1and3turnedouttoberutilephaseTiO2-awhitepaint.Layer2wasaGoethite,aredpigmentandcorrosioninhibitor.Layer4wasmolybdateorange,acommonredpaintinthe70’sinNorthAmericaandstillusedintheU.K.today.Layer5wasasilicatebasedpaint.DataarisingfromacaseinvestigatedbyLAPD.Applications-PaintChipsFore36Applications-GemForgeryIn1999anewprocesswasdeveloped–calledGEPOL–wherebybrowntypeIIadiamondscouldbetreatedtobecomeindistinguishablefromnaturallycleardiamonds.Ramanpresentedwaytodistinguishthem.NaturallycleardiamondOriginallybrowndiamondApplications-GemForgeryIn137Applications-BulletProofGlassIdentifypoly(carbonate)frompoly(methylmethacrylate).Bothusedforshatter-proofglassApplications-BulletProofGl38Applications-SunscreenFormulationsHerearethespectraof5commonsunscreeningredients.Ramanisabletodeterminefromaspectrumonthearmthenatureofthesunscreenbeingused.A:ODPABA(octylN,N-dimethyl-p-aminobenzoicacid)B:OMC(octylp-methoxycinnamate)C:BZ3(oxybenzone)D:OCS(octylsalicylate)E:DBM(dibenzoylmethane)G.R.Luppnowetal.,J.Raman.Spec.34,743(2003).Applications-SunscreenFormu39激光Raman光譜儀

laserRamanspectroscopy激光光源：He-Ne激光器，波長632.8nm；

Ar激光器，波長514.5nm，488.0nm；散射強(qiáng)度1/4單色器：

光柵，多單色器；檢測器：光電倍增管，光子計數(shù)器；激光Raman光譜儀

laserRamanspectr40傅立葉變換-拉曼光譜儀FT-Raman

spectroscopy光源：Nd-YAG釔鋁石榴石激光器（1.064m）；檢測器：高靈敏度的銦鎵砷探頭；特點(diǎn)：（1）避免了熒光干擾；（2）精度高；（3）消除了瑞利譜線；（4）測量速度快。傅立葉變換-拉曼光譜儀FT-Ramanspectrosco41SourcesRamanintensityisweakandtheexcitationsourcemustbestrongtogeneratesufficientsignal.Sourcemustbemonochromaticsothatspectrumissufficientlyuncomplicated.Intenselampscanwork,butwhenmonochromatized,haveverylittlepower.Scatteringefficiencyincreasesasn4:thebluerthelight,themorethescattering.Thebluerthelight,thegreaterthechanceofproducingfluorescence.Lasersareusedalmostexclusively.Ar+Ion:488.0and514.5nmKr+Ion:530.9and647.1nmHe:Ne:632.8nmDiodeLasers:782and830nmNd:YAG:1064(532whendoubled)nmIjustchecked.Hereisa500mWArionlaserforsaleoneBayfor$1000.SourcesRamanintensityisweak42Sources-1Experimentusedtorequireconsiderableexcitationpower Ionlasers,40Wcw He:Ne,10Wcw YAG,1J/10nspulse(100MWaveragepulse)Butdetectorshaveimprovedsomuch,thesourcepowerrequirementshavebeendecreased. Diodelaser,25mW otherlaserscanbemadecorrespondinglysmaller.Sources-1Experimentusedtore43DetectorsScatteredlightislowintensity,sohighgainPMT’shavebeenusedinthepast.ThiswasusedforscannedandFT-Ramaninstrumentationformanyyears.NowcooledCCDarraysareused;experimentisnowmultichannel.CooledNIRdetector,1024x256pixelarray,26μmsquarepixels.FromJobinYvon.DetectorsScatteredlightislo44拉曼光譜分析法拉曼光譜分析法45RemoteRamanAnalysis

onPlanetaryMissionsToallowRamanspectroscopyatrangeof10'sofmeters.ThisNASA-fundedprojectisaimedatMarslandersorlandersonotherplanets,butalsohasterrestrialuses.RemoteRamanAnalysis

onPlan46激光拉曼光譜基本原理Rayleigh散射：彈性碰撞；無能量交換，僅改變方向；Raman散射：非彈性碰撞；方向改變且有能量交換；Rayleigh散射Raman散射E0基態(tài)，E1振動激發(fā)態(tài)；E0+h0，

E1+h0激發(fā)虛態(tài)；獲得能量后，躍遷到激發(fā)虛態(tài).（1928年印度物理學(xué)家RamanCV發(fā)現(xiàn)；1960年快速發(fā)展）

h

E0E1V=1V=0h0h0h0h0+

E1+h0E0+h0h(0-

)激發(fā)虛態(tài)激光拉曼光譜基本原理Rayleigh散射：Rayleigh散47基本原理1.Raman散射Raman散射的兩種躍遷能量差：

E=h(0-

)產(chǎn)生stokes線；強(qiáng)；基態(tài)分子多；

E=h(0+

)產(chǎn)生反stokes線；弱；Raman位移：Raman散射光與入射光頻率差；ANTI-STOKES0-

RayleighSTOKES0+

0h(0+

)E0E1V=1V=0E1+h0E2+h0

h

h0h(0-

)基本原理1.Raman散射ANTI-STOKES0-48Rayleigh/RamanTransitionsIRAbsorptionsRayleigh/RamanTransitionsIR49Rayleigh/RamanTransitionsandSpectraRayleigh/RamanTransitionsa50Rayleigh/RamanTransitionsandSpectraRayleigh/RamanTransitionsa51TheSpectrumAcompleteRamanspectrumconsistsof:?aRayleighscatteredpeak(highintensity,samewavelengthasexcitation)?aseriesofStokes-shiftedpeaks(lowintensity,longerwavelength)?aseriesofanti-Stokesshiftedpeaks(stilllowerintensity,shorterwavelength)?spectrumindependentofexcitationwavelength(488,632.8,or1064nm)SpectrumofCCl4,usinganAr+laserat488nm.TheSpectrumAcompleteRamans52RamanSpectroscopyAnotherspectroscopictechniquewhichprobestherovibrationalstructureofmolecules.C.V.Ramandiscoveredin1928;receivedNobelPrizein1931.Canprobegases,liquids,andsolids.Mustusealasersourceforexcitation.Resurgenceinrecentyearsduetothedevelopmentofnewdetectorswithimprovedsensitivity.ShiftbackawayfromFT-RamantodispersiveRamanwithmultichanneldetectorsystems.RamanSpectroscopyAnotherspec53InfraredandRamanSpectraofBenzeneIRRamanInfraredandRamanSpectraof54拉曼光譜與紅外光譜分析方法比較拉曼光譜與紅外光譜分析方法比較55SomeRamanAdvantagesHerearesomereasonswhysomeonewouldprefertouseRamanSpectroscopy.?Non-destructivetosamples(minimalsampleprep)?Highertemperaturestudiespossible(don’tcareaboutIRradiation)?Easilyexaminelowwavenumberregion:100cm-1readilyachieved.?Bettermicroscopy;usingvisiblelightsocanfocusmoretightly.?Easysampleprep:waterisanexcellentsolventforRaman.Canprobesamplethroughtransparentcontainers(glassorplasticbag).SomeRamanAdvantagesHereare56WatchforFluorescenceSpectrumofanthracene.A:usingAr+laserat514.5nm.B:usingNd:YAGlaserat1064nm.Wanttouseshortwavelengthbecausescatteringdependson4thpoweroffrequency.…BUT…Wanttouselongwavelengthtominimizechanceofinducingfluorescence.WatchforFluorescenceSpectrum57紅外活性和拉曼活性振動①紅外活性振動

ⅰ永久偶極矩；極性基團(tuán)；ⅱ瞬間偶極矩；非對稱分子；紅外活性振動—伴有偶極矩變化的振動可以產(chǎn)生紅外吸收譜帶.②拉曼活性振動

誘導(dǎo)偶極矩=E非極性基團(tuán)，對稱分子；拉曼活性振動—伴隨有極化率變化的振動。對稱分子：對稱振動→拉曼活性。不對稱振動→紅外活性

Eeer紅外活性和拉曼活性振動①紅外活性振動紅外活性振動—伴有偶極矩58SelectionRuleforRamanScatteringMustbechangeinpolarizabilityNon-PolargroupssuchasC-S,S-S,C=C,CC(triplebond),N=Nandheavyatoms(I,Br,Hg)strongscatterersSymmetricstretchingvibrationsaremuchstrongerscatterersthanasymmetricstretchingvibrationsSelectionRuleforRamanScatt59PolarizationEffectsPolarizationEffects60對稱中心分子CO2，CS2等，選律不相容。無對稱中心分子（例如SO2等），三種振動既是紅外活性振動，又是拉曼活性振動。選律1234拉曼活性紅外活性紅外活性振動自由度：3N-4=4拉曼光譜—源于極化率變化紅外光譜—源于偶極矩變化對稱中心分子CO2，CS2等，選律不相容。選61PolarizationofCCl4

PolarizationofCCl462PolarizationofCHCl3

PolarizationofCHCl363Raman位移

對不同物質(zhì)：不同；對同一物質(zhì)：與入射光頻率無關(guān)；表征分子振-轉(zhuǎn)能級的特征物理量；定性與結(jié)構(gòu)分析的依據(jù)；Raman散射的產(chǎn)生：光電場E中，分子產(chǎn)生誘導(dǎo)偶極距=E

分子極化率；Raman位移對不同物質(zhì)：不同；64由拉曼光譜可以獲得有機(jī)化合物的各種結(jié)構(gòu)信息：2）紅外光譜中，由CN，C=S，S-H伸縮振動產(chǎn)生的譜帶一般較弱或強(qiáng)度可變，而在拉曼光譜中則是強(qiáng)譜帶。3）環(huán)狀化合物的對稱呼吸振動常常是最強(qiáng)的拉曼譜帶。1）同種分子的非極性鍵S-S，C=C，N=N，CC產(chǎn)生強(qiáng)拉曼譜帶，隨單鍵雙鍵三鍵譜帶強(qiáng)度增加。拉曼光譜與有機(jī)結(jié)構(gòu)由拉曼光譜可以獲得有機(jī)化合物的各種結(jié)構(gòu)信息：2）紅外光譜中，654）在拉曼光譜中，X=Y=Z，C=N=C，O=C=O-這類鍵的對稱伸縮振動是強(qiáng)譜帶，反這類鍵的對稱伸縮振動是弱譜帶。紅外光譜與此相反。5）C-C伸縮振動在拉曼光譜中是強(qiáng)譜帶。6）醇和烷烴的拉曼光譜是相似的：I.C-O鍵與C-C鍵的力常數(shù)或鍵的強(qiáng)度沒有很大差別。II.羥基和甲基的質(zhì)量僅相差2單位。III.與C-H和N-H譜帶比較，O-H拉曼譜帶較弱。4）在拉曼光譜中，X=Y=Z，C=N=C，O=C=O-這類鍵66紅外與拉曼譜圖對比紅外光譜：基團(tuán)；拉曼光譜：分子骨架測定；紅外與拉曼譜圖對比紅外光譜：基團(tuán)；67紅外與拉曼譜圖對比紅外與拉曼譜圖對比68RamanandInfraredSpectraofH-C≡C-HAsymmetricC-HStretchSymmetricC-HStretchC≡CStretchRamanandInfraredSpectraof69Vibrationalmodesofmethane(CCl4)Infraredinactive,RamanactivevibrationsInfraredactive,Ramaninactivevibrations314cm-1776cm-1463cm-1219cm-1Vibrationalmodesofmethane(70InfraredandRamanSpectrumofCCl4776cm-1314cm-1463cm-1219cm-1InfraredspectrumRamanspectrumInfraredandRamanSpectrumof712941，2927cm-1

ASCH22854cm-1

SCH21029cm-1

（C-C）803cm-1環(huán)呼吸

1444，1267cm-1

CH22941，2927cm-1ASCH22854cm-1723060cm-1r-H)1600,1587cm-1c=c)苯環(huán)1000cm-1環(huán)呼吸787cm-1環(huán)變形1039,1022cm-1單取代3060cm-1r-H)1600,1587cm-173RamanSpectroscopyRelativelysimpleandnon-destructivestructureanalysistechniqueofcarbonmaterialsPowerfultoolforthestructuralcharacterizationofdiamondoramorphouscarbonmaterials.DLCDiamondRamanSpectroscopyRelativelys74RemoteRamanAnalysis

onPlanetaryMissionsToallowRamanspectroscopyatrangeof10'sofmeters.ThisNASA-fundedprojectisaimedatMarslandersorlandersonotherplanets,butalsohasterrestrialuses.RemoteRamanAnalysis

onPlan75NSOMRamanImagingSpectrumofpotassiumtitanylphosphate.FromHansHallenatNCSU.Squaresare5x5μmsquareofthismaterialdopedwithRb.Anear-fieldscanningmicroscopewasusedandtheRamansignalwasusedtokeythesubstrateresponse.NSOMRamanImagingSpectrumof76ChemicalMappingFocuslasertosmallspot.TunespectrometertoparticularRamantransitionpeak.Rasterscanthesampleunderthelaserbeam,recordintensitychanges.Resultantmapcorrelateswithsubstance.Acquireanentirespectrumateverypoint,thenchoosethefeaturewithwhichtokeytheimage.MotorizedstagefromRenishawforchemicalmapping.Thisisadrugtablet.Theyellowcorrespondstotheactiveingredient.Particlesareinthe10’sofμmrange.ChemicalMappingFocuslaserto77ChemicalImagingNowdefocusthelaser(notasmallspotbutrather“baths”thesampleinlaserradiation).Passtheemittedradiationthroughanarrowbandpassfilter,adjustedtoaparticularwavelength,chosentobeacertainRamanband.FocusthislightontheCCDcamera.BrightregionscorrespondtolocationsofsubstancegivingrisetoRamansignal.Mixtureofcocaineandsugar.Brightspotsarecocaine.ChemicalImagingNowdefocusth78Applications-ArtRestorationThis12centuryfrescoonachurchwallinItalyneededtoberestored.Whatpaintstouse?Ramananalysisclearlyidentifiedthepaintsandpigmentsthatwereoriginallypresent,permittingacorrectchoiceofcleaningmaterialsandsubsequentrepaintingtorestoreitsoriginalcondition.Applications-ArtRestoration79Applications-PaintChipsForensicanalysisofpaintchipsinvehicleaccidents.Oftenmultiplelayers.CananalyzewithIRbystrippingsuccessivelayers.ImageedgewithmicroRaman.Layers1and3turnedouttoberutilephaseTiO2-awhitepaint.Layer2wasaGoethite,aredpigmentandcorrosioninhibitor.Layer4wasmolybdateorange,acommonredpaintinthe70’sinNorthAmericaandstillusedintheU.K.today.Layer5wasasilicatebasedpaint.DataarisingfromacaseinvestigatedbyLAPD.Applications-PaintChipsFore80Applications-GemForgeryIn1999anewprocesswasdeveloped–calledGEPOL–wherebybrowntypeIIadiamondscouldbetreatedtobecomeindistinguishablefromnaturallycleardiamonds.Ramanpresentedwaytodistinguishthem.NaturallycleardiamondOriginallybrowndiamondApplications-GemForgeryIn181Applications-BulletProofGlassIdentifypoly(carbonate)frompoly(methylmethacrylate).Bothusedforshatter-proofglassApplications-BulletProofGl82Applications-SunscreenFormulationsHerearethespectraof5commons