中文摘要：

研究了苯甲酸及其甲基取代物在248nm激光作用下的光电离及光激发行为，测定了光电离量子产额和激发三线态寿命及其自猝灭速率常数。实验结果显示甲基在苯环不同位置的取代对苯甲酸化合物激发三线态的影响不明显。利用分步双激光技术对苯甲酸激发态进行共振激发，对可能生成的瞬态产物进行了初步探讨。

英文摘要：

In the present paper the photo-ionization and properties of excited state of benzoic acid and its methyl substitutes were studied using 248 nm laser flash photolysis. The quantum yields of hydrated electrons produced from photo-ionization, the lifetime of excited triplet, and the self quenching rate constants were also determined, it is shown that there isn＇t significant effect of different position of methyl residue at benzene ring on its excited triplet. The resonant excitation of triplet of benzoic acid was explored by the use of two-steps laser flash photolysis. The possible upper excited state and radical involved in the processes were guessed.