Emission Spectrum

The term you're referring to is the "emission". An emission spectrum is a spectrum of frequencies of electromagnetic radiation emitted by an atom or molecule when it transitions from a higher energy state to a lower energy state. This emission of light or other electromagnetic radiation is characteristic of the particular element or compound, and it can be used to identify and study them. Each element or compound has a unique emission spectrum, which can be observed as specific lines or bands of light at distinct wavelengths or frequencies, depending on the energy-level transitions involved. This information is fundamental in fields like spectroscopy and chemistry for analyzing and identifying substances.