chemiluminescence

noun

1. (in chemical reactions) the emission of light by an atom or molecule that is in an excited state.

noun

1. the phenomenon in which a chemical reaction leads to the emission of light without incandescence

1. The emission of light by a substance as a result of undergoing a chemical reaction that does not involve an increase in its temperature. Chemiluminescence usually occurs when a highly oxidized molecule, such as a peroxide, reacts with another molecule. The bond between the two oxygen atoms in a peroxide is relatively weak, and when it breaks the atoms must reorganize themselves, releasing energy in the form of light. Compare bioluminescence.