Question

Explain why Infrared spectroscopy uses interferometers rather than constant wavelength spectrometers.

Answer 1

An infrared spectroscopy is used to find the nature and type of atom or molecule present in a particular compound. It can absorb a range of wavelength from near IR to far IR in the electromagnetic spectrum. It can absorb the frequencies corresponding to the vibration of molecules present in it and will help to identify the atom or molecule. So interferometer used to analyze the light containing features of absorption or emission associated with a particular substance.

but in constant wavelength spectrometer like UV visible spectro photometer, only the absorption at that particular wavelength will obtain, The absorption or emission at different wavelength cannot be superimposed and will not create an interference pattern. So need to check for each wavelength separately. But Infrared spectrometer will absorb many frequencies of light and will measure how much of that beam is absorbed by the sample.