芘四磺酸钠水溶液激光闪光光解机理

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.

Laser Flash Photolysis Mechanism of Pyrenetetrasulfonate in Aqueous Solution

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× 10⁵ 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.