absorption line - definition - light, atomic and molecular physics, quantum mechanics, spectroscopy

Definition: Dark lines in a continuous spectrum of white light caused by absorption by a gaseous element. The lines correspond to the same light frequencies that would be emitted by the gaseous element if it was given energy, either through heat, electricity, light or some other agency.

Also Known As: absorption spectrum, spectral lines.

Examples: The absorption lines in the spectrum of the sun (also known as the Fraunhoffer lines) tell us about the composition of both the sun and the upper atmosphere.