An Etymological Dictionary of Astronomy and Astrophysics

A specific type of → photoluminescence that continues for an appreciable time after the stimulating process has ceased. Phosphorescence is due to the existence of metastable → excited states of the atoms and molecules from which a change to the normal state is hindered for some reason or other. The change from the → metastable metastable state to the normal one becomes possible only as a result of some additional excitation, for example the application of heat.

See also: → phosphorus; → -escence.