lifetime

of luminescence
https://doi.org/10.1351/goldbook.L03516
The time required for the @L03641@ intensity to decay from some initial value to $$\frac{1}{\text{e}}$$ of that value ($$\text{e} = 2.718\,...$$). Lifetimes can be measured by @P04529@ (@F02416@) where the phase shift between the sinusoidally modulated exciting light and the emitted light is measured.
Source:
PAC, 1984, 56, 231. (Nomenclature, symbols, units and their usage in spectrochemical analysis-Part VI: molecular luminescence spectroscopy) on page 242 [Terms] [Paper]