spectroscopy science definition

The analysis of spectra, especially light or mass spectra, to determine properties of their source.
♦ In light  or optical spectroscopy, the spectrum of a light source is analyzed through a spectroscope to determine atomic composition of a substance. In astronomy, phenomena such as red shift  can also be analyzed.
♦ In mass spectroscopy , a spectroscope is used to determine the composition of ions or charged molecules in a sample. Spectroscopy is also called spectrography. See also atomic spectrum, spectroscope.