The document discusses infrared (IR) spectroscopy. It provides information on: - The ideal features of an IR spectrum and how it is represented as absorption bands between transmittance and wave number. - The two main regions of absorption - the functional group region (FGR) and fingerprint region (FPR) - and how they are used to identify functional groups and provide molecular fingerprints. - Common functional groups and their absorption ranges to guide interpretation of spectra. - The requirements for a proper IR spectrum and interpretation, including sample purity and spectrophotometer calibration. - Sources of reference data like literature, charts and libraries to aid analysis.