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ENERGY TRANSFER IN PHENANTHRENE‐DOPED NAPHTHALENE CRYSTALS
Author(s) -
HUNTER T. F.
Publication year - 1969
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1969.tb07302.x
Subject(s) - phenanthrene , phosphorescence , naphthalene , photochemistry , chemistry , singlet state , excited state , fluorescence , exciton , atomic physics , organic chemistry , physics , optics , quantum mechanics
— Measurements at 77°K and room temperature are described on naphthalene crystals containing varying concentrations of phenanthrene. The lowest excited singlet and triplet states of phenanthrene iie between the singlet and triplet exciton bands of the host crystal. Triplet‐triplet annihilation in the host was studied by absorbing radiation purely into the guest molecules; the absence of any phosphorescence or delayed naphthalene fluorescence allowed the radiationless processes out of the naphthalene triplet to be discussed. Singlet‐singlet energy transfer was studied using radiation absorbed by the naphthalene. Two separate mechanisms of transfer were observed: (A) free exciton motion in the naphthalene band till encounter with a phenanthrene trap, the last step having an activation energy of 65 cm ‐1 , and (B) defect traps in the naphthalene transferring energy by a resonance mechanism to the phenanthrene; the average depth of the defect traps was calculated at 200 cm ‐1 .