Luminescence

**Definition:** Emission of LIGHT when ELECTRONS return to the electronic ground state from an excited state and lose the energy as PHOTONS. It is sometimes called cool light in contrast to INCANDESCENCE. LUMINESCENT MEASUREMENTS take advantage of this type of light emitted from LUMINESCENT AGENTS.

**Tree numbers:** - G01.358.500.505.650.665 - G01.590.540.665 - G01.750.250.650.665 - G01.750.770.578.665

**Synonyms:** - Luminescence, Physical