Evidence for a non-RRKM photochemical decay. Triplet state behavior of alicyclic ketones
✍ Scribed by E. Hamer; J.Robert Huber
- Publisher
- Elsevier Science
- Year
- 1978
- Tongue
- English
- Weight
- 400 KB
- Volume
- 55
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Sy means of triplet-triplet energy transfer to biacetyl, the population of the VibrationalIy xelaxed triplet state Ty of the alicyclic ketones cycloheptanone, cyclohexanonc, and cyclopentanone was examined as a function of the excitation wavelength. This popuiation. as measured in terms of the ketone triplet yield @f(A), was compared with the excitation energy dependence of the photochemical quantum yield. This comparison demonstrated that the main photochemical path of these ketones originates from higher vibrational levels cf T1. Thus, w(A) reflects the branching ratio between a non-RRKM photochemical decay and the vibrational relaxation process to Tr. Moreover, @&I) was found to decrease significantly in the order cycloheptauone > cyclobexanone > cyclopgntanone. This observztion reflects, at least in part, the influence of the internal degrees of freedom on the vibrational reiaxation rate.