Triplet-triplet absorption spectra of coumarin and 7-hydroxycoumarin in rigid alcoholic solutions at 117°K were recorded. Measurement of ground state depletion allowed the determination of the molar extinction coefficients of the triplet bands, for both compounds. CNDO/S calculations of the triplet-triplet transitions were performed and an assignment of the observed bands was attempted. © 1974.
Crozet, P. (1974). Triplet-triplet absorption of coumarin and 7-hydroxycoumarin. Chemical Physics Letters, 25(1), 114–118. https://doi.org/10.1016/0009-2614(74)80346-5