Mechanism of the excited singlet and triplet states quenching by molecular oxygen in acetonitrile
Mechanism of the excited singlet and triplet states quenching by molecular oxygen in acetonitrile
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DOI：
10.1016/j.jphotochem.2004.12.006
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发表时间：
2005-05-31
影响因子：
4.3
通讯作者：
Worrall, DR
中科院分区：
文献类型：
--
作者：
Abdel-Shafi, AA;Worrall, DR
本文报道了某些芳烃在乙腈中被分子氧激发单重态和三重态猝灭的速率常数k（q）（S）和k（q）（T）。被氧淬灭的激发单重态的分数f（T）（S）在0.25-0.85的范围内，其导致三重态。还测量了在激发单重态和三重态的氧猝灭期间单线态氧产生的效率，分别为f（Delta）（S）和f（Delta）（T）。对于1，2; 5，6-二苯并蒽、芘、荧蒽、1，11-苯并二萘和二萘，f（Delta）（S）的值显示为0.28 +/-0.05，而f（Delta）（T）的值覆盖0.25-1.0的范围。总猝灭速率常数与分数效率的组合允许获得用于各种氧猝灭途径的单独的净猝灭速率常数。讨论了氧对激发单重态和三重态猝灭过程中产生不同效率的单重态氧的影响因素。(c)2004 Elsevier B. V.保留所有权利。
Rate constants for quenching by molecular oxygen of excited singlet and triplet states, k(q)(S) and k(q)(T), respectively, of some aromatic hydrocarbons in acetonitrile are reported. The fraction of excited singlet states quenched by oxygen which result in triplet states, f(T)(S), are in the range of 0.25-0.85. The efficiencies of singlet oxygen production during oxygen quenching of the excited singlet and triplet states, f(Delta)(S), and f(Delta)(T) respectively, were also measured. Values of f(Delta)(S) were shown to be 0.28 +/- 0.05 for 1,2;5,6-dibenzanthracene, pyrene, fluoranthene, 1, 11-benzoperlyene and perlyene while values of f(Delta)(T) cover the range of 0.25-1.0. Combination of the total quenching rate constants with the fractional efficiencies allows separate net quenching rate constants to be obtained for the various oxygen quenching pathways. Factors governing the production of singlet oxygen with different efficiencies during quenching of both excited singlet and triplet states by oxygen are discussed. (c) 2004 Elsevier B.V. All rights reserved.