Difference Between Spectroscopy and Spectrometry -

Spectroscopy vs Spectrometry

Spectroscopy and spectrometry are two widely discussed topics in fields such as chemistry and astronomy. This article covers the basics, similarities, and differences between spectrometry and spectroscopy.


Spectroscopy is the study of the interaction between matter and radiated energy. This can be interpreted as the science of studying the interactions of matter and radiation. To understand spectroscopy, one must first understand spectrum. The visible light is a form of electromagnetic waves. There are other forms of EM waves such as X-Rays, Microwaves, Radio waves, Infrared and Ultraviolet rays. The energy of these waves is dependent on the wavelength or the frequency of the wave. High frequency waves have high amounts of energies, and low frequency waves have low amounts of energies. The light waves are made up of small packets of waves or energy known as photons. For a monochromatic ray, the energy of a photon is fixed. The electromagnetic spectrum is the plot of the intensity versus the frequency of the photons. When a beam of waves having the whole range of wavelengths is passed through some liquid or gas, the bonds or electrons in these materials absorb certain photons from the beam. It is due to the quantum mechanical effect that only photons with certain energies get absorbed. This can be understood using the energy level diagrams of atoms and molecules. Spectroscopy is studying the incident spectrums, emitted spectrums and absorbed spectrums of materials.


Spectrometry is the method used for the study of certain spectrums. Ion-mobility spectrometry, mass spectrometry, Rutherford backscattering spectrometry, and neutron triple axis spectrometry are the main forms of spectrometry. In these cases, a spectrum does not necessarily mean a plot of intensity versus frequency. For example, the spectrum for mass spectrometry is the plot between intensity (number of incident particles) versus the mass of the particle. Spectrometers are the instruments used in spectrometry. The operation of each type of instrument depends on the form of spectrometry used in the instrument. Spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. For the visible region, the perfect white light contains all the wavelengths within the region. Assume, white light is sent through a solution absorbing photons with a wavelength of 570 nm. This means the red photons of the spectrum is now reduced. This will cause a blank or reduced intensity at the 570 nm mark of the plot of intensity versus wavelength. The intensity of the light passed, as a proportion to the light projected, can be plotted for some known concentrations, and the resultant intensity from the unknown sample can be used to determine the concentration of the solution.

What is the difference between Spectrometry and Spectroscopy?

• Spectroscopy is the science of studying the interaction between matter and radiated energy while spectrometry is the method used to acquire a quantitative measurement of the spectrum.

• Spectroscopy does not generate any results. It is the theoretical approach of science. Spectrometry is the practical application where the results are generated.