https://doi.org/10.1351/goldbook.M03991
A @G02585@ which makes use of electronic, vibrational or rotational energy levels in molecules. The molecules can be excited by an electric discharge, as in the case of the N2 or CO2 @L03459@, by chemical reactions, as in the HF or DF lasers, or by another @L03459@, as in the CH3F far IR @L03459@.