中文摘要：

利用时间分辨电子自旋共振（TmESR）方法，研究了稳定自由基TEMPO和生物抗氧化剂维生素C（VC）对萘醌（NQ）激发三重态。NQ＊的猝灭机理和猝灭动力学。光解NQ／EG体系，^3NQ＊从EG上抽氢生成萘醌中性自由基NQH＊和乙二醇碳自由基CH2CH（OH）2。当体系中加入稳定自由基TEMPO时，TEMPO对^3NQ＊有明显的猝灭作用，猝灭速率常数为1．14×10^7L·mol^-1·S^-1。对于NQ／VC／EG-H2O溶液，^3NQ＊不仅可以从EG上夺氢，还从VC上夺氢，VC对^3NQ＊也有明显的猝灭作用，猝灭速率常数为1．11×10^7L-mol^-1·S^-1。TEMPO和VC对^3NQ＊的猝灭反应都受扩散控制。

英文摘要：

The reaction mechanism and dynamics of the laser induced excited triplet of 1,4-naphthoquinone （^3NQ＊） quenched by TEMPO and biological antioxidant vitamin C （VC） were investigated by means of time resolution electron spin resonance （TR-ESR） method. During the photolysis of NQ/EG （ethylene glycol） solution, ^3NQ＊ abstracts hydrogen atom from solvent molecule EG. and the neutral radical NQH＊ and EG ketyl radical CH2CH（OH）2 were generated. When TEMPO was added into NQ/EG solution, TEMPO is an effective quencher of 3NQ＊ and the quenching rate constant is 1.14×10^7L·mol^-1·S^-1. For NQ/VC/EG-H20 solution, 3NQ＊ abstracts hydrogen atom not only from solvent EG but also from VC. VC is also an effective quencher of 3NQ＊ and the quenching rate constant is 1.11×10^7L-mol^-1·S^-1. The quenching reactions of ^3NQ＊ by TEMPO and VC are both controlled by diffusion.