采用激光闪光光解-瞬态吸收光谱技术研究了355nm激光作用下芘四磺酸钠(PyTS)水溶液的光化学反应机理及其产生水合电子的动力学行为.研究首次发现PyTS水溶液激发单线态(PyTS1*)在260nm、激发三线态(PyTS3*)在300nm及阴离子自由基(PyTS-?)在330nm处的特征吸收峰;分析了生成的水合电子(e-aq)的主要反应途径包括自猝灭反应及与PyTS的反应,得到水合电子与PyTS反应的准一级速率常数为2.7′105s-1;并计算得到在此实验条件下,PyTS水溶液经双光子吸收产生的水合电子量子产率为3.2′10^-2.
The mechanism of photochemical reactions of pyrenetetrasulfonate(PyTS)in aqueous solution was studied using laser flash photolysis-transient absorption spectrum techniques under irradiation at 355 nm.The characteristic absorption peaks of the excited singlet(PyTS 1* )at 260 nm,the excited triplet(PyTS 3* )at 300 nm,and the anion radical(PyTS -* )at 330 nm were first confirmed. Self-quenching and reaction with PyTS were regarded as the main decay channels for hydrated electrons (e - aq ),and the pseudo-first-order rate constant of hydrated electrons with PyTS was determined to be 2.7′ 10 5 s ?1 .The quantum yield of e - aq generated via two-photon ionization of PyTS was computed to be 3.2′10 ?2 under these conditions.