CH(A^2△)自由基被烷烃分子猝灭动力学的温度效应研究  

Temperature Effect on Quenching of CH(A^2△) by Alkane

作　　者：王非[1] 陈益新 冉琴[1] 裴林森[1] 陈从香[1] 马兴孝[1] 

机构地区：[1]中国科学技术大学化学物理系,合肥230026

出　　处：《Chinese Journal of Chemical Physics》1999年第4期385-389,共5页化学物理学报（英文）

基　　金：国家自然科学基金!No.2973117

摘　　要：用266nm激光光解CHBr3产生CH自由基，利用精密控温仪控制反应温度，测定CH（A→X）荧光的时间分辨信号，测量了290～593K范围内CH（A2△）被正戊烷、正己烷、正庚烷猝死的速率常数．实验结果表明，猝灭速率常数都有随温度升高而上升的趋势，但不符合Arrhenius关系式所描述的变化趋势。用公式k＝A（T）exp（－Ea／RT）对温度效应进行了拟合，拟合效果令人满意．并利用修正的碰撞络合物模型，定性地解释了在多极吸引势与活化势垒的双重影响下，猝灭截面与温度间的关系．The quenching rate constants of CH(A2△) radicals by n -C5H12, n-C6H14, n -C7H16between 290K and 593K have been measured using laser photolysis of CHBr3 at 266nm to produce CH radicals, time-resolved fluorescence quenching measurements and tempefature controller to control the temperature of the reactor. The experiment results show that the quenching rate constants all increase with the increase of temperature. But the temperature dependence does not fit the Arrhenius expression. We fitted the relation between the quenching rate constant and temperature to k=ATnexp(-Ea/RT). The simulated results are satisfied. Under the simultaneous effects of multipole attractive potential and barrier, the temperature dependency is analysised qualitatively based on a modified collision complex model.

关 键 词：烷烃 猝灭 碰撞络合物 温度效应 次甲基自由基 

分 类 号：O621.146[理学—有机化学] X124[理学—化学]