Resonance fluorescence
Resonance fluorescence is a special case of fluorescence that occurs when atoms are excited with electromagnetic waves , for example with light . An atom with discrete energy levels is first brought into an excited state with a photon of the appropriate wavelength λ ex (e.g. yellow light for the sodium D line ) . A little later it falls back to its ground state and spontaneously emits a photon of the same wavelength λ em = λ ex .
In contrast to fluorescence with more complex dye molecules (e.g. fluorescein or green fluorescent protein ) there is no Stokes shift λ ex - λ em between excitation and fluorescence photons. This is due to the fact that atoms do not relax radiation-free through vibration.
In addition to the absorption of the photon in the atomic shell , the atomic nucleus can also absorb high-energy photons . When the nucleus then goes into the ground state in one step, the emitted photon has the same energy. A higher-energy photon is known as nuclear magnetic resonance fluorescence .
See also
Individual evidence
- ↑ Entry on Resonance Fluorescence . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.R05335 Version: 2.3.3.