Material characterization-IR-151204

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1、Material characteriza;on‐材料表征Infrared spectroscopy (IR) Fourier transform infrared spectroscopy (FTIR)芦红Tel: 83592767  Email: hlu@nju.edu.cn12/04/2015Raman vs Infrared SpectraMcCreery,R.L.,RamanSpectroscopyforChemicalAnalysis,3rded.,Wiley,NewYork:20002Advantages of R

2、aman over IR•Watercanbeusedassolvent.•Verysuitableforbiologicalsamplesinnativestate(becausewatercanbeusedassolvent).•AlthoughRamanspectraresultfrommolecularvibrationsatIRfrequencies,spectrumisobtainedusingvisiblelightorNIRradiation.=>Glassandquartzlenses,cells,andopt

3、icalfiberscanbeused.Standarddetectorscanbeused.•Fewintenseovertonesandcombinationbands=>fewspectraloverlaps.•Totallysymmetricvibrationsareobservable.3•Ramanintensitiesαtoconcentrationandlaserpower.Advantages of IR over Raman•Simplerandcheaperinstrumentation.•Lessinst

4、rumentdependentthanRamanspectrabecauseIRspectraarebasedonmeasurementofintensityratio.•Lowerdetectionlimitthan(normal)Raman.•BackgroundfluorescencecanoverwhelmRaman.•Moresuitableforvibrationsofbondswithverylowpolarizability(e.g.C–F).4Infrared(IR)Spectroscopy•IRdealswi

5、ththeinteractionofinfraredradiationwithmatter.TheIRspectrumofacompoundcanprovideimportantinformationaboutitschemicalnatureandmolecularstructure.•Mostcommonly,thespectrumisobtainedbymeasuringtheabsorptionofIRradiation,althoughinfraredemissionandreflectionarealsoused.•

6、Widelyappliedintheanalysisoforganicmaterials,alsousefulforpolyatomicinorganicmoleculesandfororganometalliccompounds.5Overview1.Electromagneticradiation2.Vibrations3.PrincipleofIRexperiment4.IRspectrum5.Typesofvibration6.CGF/Fingerprintregions7.IRactivityofvibrations8

7、.InterpretationofIRspectra9.Instrumentation10.Samplepreparation6ElectromagneticRadiationThepropagationofelectromagneticradiationinavacuumisconstantforallregionsofthespectrum(=velocityoflight):c=λ×ν1Å=10–10m1nm=10–9m1µm=10–6mAnotherunitcommonlyusedisthewavenumber,whic

8、hislinearwithenergy:WorkbyEinstein,PlanckandBohrindicatedthatelectromagneticradiationcanberegardedasastreamofparticlesorquanta,forw