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1.3.ConstructionofaFT-IRspectrometer
15
Fig.1.2.TypesofvibrationsforXY
2molecule
(1.5)
where„*”correspondstoamoleculewithachangedisotope.
Itisalsoassumedthataconsiderableshiftisonlyobservedforbandsthatrep-
resent“isolated”vibrationsoffunctionalgroups.
1030ConstructionofaFT-IRspectrometer
FourierTransformIRspectrometersoperateonthebasisofmathematicaloperation
calledFouriertransformation.Atypicalspectrometerconsistsofalightsource,an
interferometer,asamplechamberandadetector.
103010Lightsource
AsourceoflightintheIRspectrometermustbepolychromaticinfraredradiation
duetothenecessityoffittingitsenergytotransitionsbetweenvibrationallevels
ofallthemolecules.Typically,lightsourcesareaglobar(SiC)andaNernstrod
(ZrO
2+Y
2O
3),which-whenheatedtohightemperature-emitradiationsimilar