mid-infrared spectroscopy

physics

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June 30, 2026

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Mid-infrared spectroscopy is a technique that uses the region of the electromagnetic spectrum between 400 and 4,000 wavenumbers (cm^-1). This region is primarily associated with the internal vibrational motion of molecules. When molecules absorb infrared radiation, their bonds vibrate, and these vibrations correspond to specific energy levels.123

Infrared spectroscopy is a powerful tool for determining molecular structure because each molecule has a unique infrared spectrum, often referred to as its "fingerprint". This technique is widely used in organic chemistry to identify functional groups within molecules, such as carbon-hydrogen, carbon-carbon, and carbon-oxygen bonds. Instruments called infrared spectrophotometers measure the amount of infrared light transmitted through a sample, producing a spectrum that reveals these structural details.234

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spectroscopy
Infrared spectroscopy
… (4,000–12,500 inverse centimetres [cm⁻¹]), the mid-infrared (400–4,000 cm⁻¹), and the far infrared (10–400 cm⁻¹). With the development of Fourier-transform spectrometers, this distinction of areas has blurred and the more sophisticated instruments can cover from 10 to 25,000 cm⁻¹ by an interchange of source, beam splitter, detector, and sample cell.
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… (4,000–12,500 inverse centimetres [cm⁻¹]), the mid-infrared (400–4,000 cm⁻¹), and the far infrared (10–400 cm⁻¹). With the development of Fourier-transform spectrometers, this distinction of areas has blurred and the more sophisticated instruments can cover from 10 to 25,000 cm⁻¹ by an interchange of source, beam splitter, detector, and sample cell.
Read More