In molecular chemistry, functional groups are substructures consisting of a few atoms with a characteristic composition and structure. Within the molecule, functional groups are often a reactive part and define or at least influence the chemical properties of compounds. Determining the presence or absence of functional groups is important for chemists to to confirm the structure of a synthesized compound. The measurement of infrared (IR) spectra is one of the most established methods to identify functional groups within organic molecules even in those cases where the most common techniques such as NMR spectroscopy fail. IR spectra are gained as a result from the interaction of infrared light with molecules. The absorption of infrared radiation induces molecular vibrations, i.e. periodic distortions of the molecular structure, including stretching, contracting, bending, and torsional motions of bonds, angles, dihedral angles, and further collective variables. By analyzing spectral parameters such as absorption energy band position, bandwidth, and absorption coefficient, one can deduce valuable information about the molecule's structure and functional groups .