triplet-triplet absorption

https://doi.org/10.1351/goldbook.T06504
@A00036@ which takes place with the transition from the lowest @T06503@ of the molecule to higher triplet states (T → $$T_{n}$$) thus leading to the triplet-triplet @A00043@.
Source:
PAC, 1984, 56, 231. (Nomenclature, symbols, units and their usage in spectrochemical analysis-Part VI: molecular luminescence spectroscopy) on page 234 [Terms] [Paper]