Infrared spectroscopy analysis Infrared spectrum analysis refers to the analysis and identification of material molecules using infrared spectroscopy. A beam of infrared rays of different wavelengths is irradiated on a molecule of a substance, and certain specific wavelengths of infrared rays are absorbed to form the infrared absorption spectrum of the molecule. Each molecule has a unique infrared absorption spectrum determined by its composition and structure, which allows for structural analysis and identification of the molecule. Infrared absorption light Spectrum is generated by the continuous vibration and rotational motion of molecules. Molecular vibration refers to the relative motion of each atom in a molecule near its equilibrium position. Polyatomic molecules can form various vibrational patterns. When atoms in a molecule undergo harmonic vibrations near the equilibrium position at the same frequency and phase, this mode of vibration is called normal vibration (such as stretching vibration and variable angle vibration). The energy of molecular vibration corresponds exactly to the quantum energy of infrared radiation. Therefore, when the vibrational state of a molecule changes, infrared spectroscopy can be emitted, and infrared absorption spectroscopy can also be generated due to the excitation of molecules by infrared radiation. The energy of molecular vibration and rotation is not continuous but quantized. However, due to the frequent accompanying rotational transitions during the vibrational transition of molecules, the vibrational spectrum is banded. So the infrared spectrum of molecules belongs to the banded spectrum