Spectroscopy technique concerned with the spectrum between the visible and the short-wavelength microwave. Infrared spectroscopy can detect the internal vibration of molecules. The field was traditionally broken into near-, mid-, and far-infrared spectroscopy, although 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.
