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Die Photochemie von Diazo‐dibenzoylmethan Eine wellenlängen‐ und temperaturabhängige Photoreaktion
Author(s) -
Baumann N.
Publication year - 1972
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19720550804
Subject(s) - chemistry , intersystem crossing , dibenzoylmethane , excited state , photochemistry , singlet state , diazo , quantum yield , population , medicinal chemistry , fluorescence , atomic physics , physics , optics , demography , sociology
Diazo‐dibenzoylmethane I undergoes two primary photochemical processes leading to α‐phenyl‐α‐benzoyl‐methane II and dibenzoylmethane III. The formation of II is related to the lowest excited singlet state of I and the formation of III is related to the lowest excited triplet state of I. The quantum yields of both processes (Φ II , Φ III ) are strongly wavelength dependent. It is unambiguously demonstrated, that the population of the two excited states depends on the energy of the exciting light, thus causing a wavelength effect. There is shown to be an activation barrier controlling the rate of intersystem crossing from the S 1 to the T 1 level of I.