resonance absorption technique

https://doi.org/10.1351/goldbook.R05327
The
monitoring
of atoms or radicals generated in the gas phase by observing the
attenuation
of the radiation from a
lamp
emitting the characteristic
resonance radiation
of the observed species.
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2271 [Terms] [Paper]