Spectroscopy ( /spɛkˈtrɒskəpi/) is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise 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.
Read more about Spectroscopy: Introduction, Theory, Classification of Methods, Other Types, Applications