Spectral Resolution in FTIR Spectroscopy

Spectral resolution is one of the most important attributes of spectrometers, since it defines the ability of the instrument to resolve bands of close proximity. The highest achievable resolution for an FTIR instrument is determined as the Full-Width at Half-Height (FWHH) for a specified spectral band measured for a low pressure gas sample in which the Doppler bandwidth is narrower than the achievable resolution of the spectrometer. Bruker uses carbon monoxide at 5 mbar for this purpose. Table 1 summarizes the achievable spectral resolution for various Bruker FTIR spectrometers. All Bruker FTIR spectrometers allow a continuous (not discrete) selection of resolution values that provides greater flexibility for spectral recording.