电子激发态CCl_2自由基被H_2O猝灭的研究

Ab INITIO CALCULATIONS ON THE REACTION MECHANISM FOR THE CCl_2 WITH H_2O AND QUENCHING OF CCl_2(A^1B_1 AND a^3B_1) BY H_2O

对CCl4 /Ar混合气体直流脉冲放电产生CCl2 自由基 ,再用 541.52nm激光将电子基态CCl2激励到激发态A1B1( 0 ,4 ,0 )振动态的K =0能级上 ,通过检测激发态CCl2 时间分辨荧光信号 ,测得室温下CCl2 (A1B1和a3B1)被H2 O分子猝灭的实验结果 ,用三能级模型分析处理实验数据 ,获得态分辨速率常数KA 和Ka 值 .利用UMP2 (Full) / 6- 31G(d ,p)方法计算了该反应的势能面 ,揭示了反应的插入和加成

CCl 2 free radicals were produced by dc discharge of CCl 4(in Ar). Ground electronic state CCl 2 radical was electronically excited to A 1B 1 (0,4,0) state K=0 level with Nd:YAG laser pumped dye laser at 541.52 nm. Experimental quenching data of CCl 2 (A 1B 1 and a 3B 1) by H 2O were obtained by observing time resolved fluorescence from the excited CCl 2 radicals transition, which showed a superposition of two exponential decay components. The state-resolved rate constants K A and Ka were acquired by analyzing and dealing with these data by using three-level-model, which was put forward by us. The extensive potential energy surface (PES) for CCl 2 with H 2O has been studied using the UMP 2(full)/6-31G(d, P). The addition-elimination reaction mechanism is revealed.