Spectroscopy is the study of the interaction between
matter and electromagnetic
radiation. Historically, spectroscopy originated through the study of
visible light dispersed according to its
wavelength, by a
prism. Later the concept was expanded greatly to include any interaction with radiative energy as a function of its wavelength or
frequency. Spectroscopic data is often represented by a
spectrum, a plot of the response of interest as a function of wavelength or frequency.