Infrared band spectrometer is an instrument that uses the absorption characteristics of substances towards infrared radiation to analyze their molecular structure and chemical composition, and is widely used in fields such as chemistry, materials, biology, and environment.
Infrared band spectrometers are mainly used to analyze the molecular structure and chemical composition of substances. It reveals the molecular structure and chemical composition of a substance by measuring its spectral response at different infrared wavelengths. The working principle of an infrared spectrometer is based on the absorption characteristics of substances towards infrared radiation. When molecules absorb infrared light, they vibrate and rotate, resulting in infrared absorption peaks. By measuring the positions and intensities of these absorption peaks, the chemical composition and molecular structure of the sample can be understood.
The infrared spectrometer mainly consists of a light source, a sample chamber, a spectrometer, a detector, and a data acquisition system. The light source generates infrared light, which is decomposed into light of different wavelengths by a spectrometer. After illuminating the sample, the sample absorbs light of a specific wavelength, and the transmitted or reflected light is captured by the detector and converted into an electrical signal, forming an infrared spectrum. By analyzing these spectra, the chemical composition and structural information of the sample can be obtained.
working principle
Molecular Vibration and Infrared Absorption
The vibration and rotational energy level transitions between atoms within a molecule are the basis for the generation of infrared spectra. When the sample is irradiated with infrared light, if the photon energy matches the vibrational or rotational energy of a specific functional group in the molecule, the functional group will absorb infrared light, causing a transition in vibrational energy levels.
The absorption process requires a change in dipole moment to form characteristic absorption peaks, with different chemical bonds or functional groups corresponding to specific absorption frequencies.
Fourier transform technique
Nowadays, Fourier transform infrared spectroscopy (FTIR) is commonly used as an infrared spectrometer, which uses a Michelson interferometer to interfere two beams of multi-color infrared light with varying optical path differences, forming an interference pattern.
The interference signal is processed by computer Fourier transform and restored to a spectral image, significantly improving the signal-to-noise ratio and resolution.