## half-life, $$\tau_{1/2}$$

of a transient entity
https://doi.org/10.1351/goldbook.HT07391
Time needed for a concentration of the entity to decrease to $$1/2$$ of its original value.
Source:
PAC, 2007, 79, 293. (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 349 [Terms] [Paper]