氯甲烷分子在13至17 eV激发能量范围内的电离解离

利用阈值光电子-光离子符合飞行时间质谱研究了氯甲烷分子在13至17eV激发能量范围内的光电离和光解离动力学.在此能量范围内,电离产生的CH3Cl+离子处于A2A1和B2E电子激发态.两电子态均为完全解离态,可生成CH3+和CH2Cl+碎片离子,其中CH3+是最主要的解离产物.拟合CH3+离子的符合飞行时间质谱峰形,可以得到CH3Cl+离子解离过程中释放的平动能分布,结果显示CH3Cl+离子A2A1态解离生成CH+3的过程接近直接解离机理,而B2E态的解离过程则具有统计解离的特征.此外,结合理论计算的势能面信息,我们推测在A2A1态出现的CH2Cl+碎片离子来源于CH3Cl分子自电离产生高振动激发的CH3Cl+(X2E)离子统计解离过程.

Ionization and Dissociation of Methyl Chloride in an Excitation Energy Range of 13-17 eV

Using threshold photoelectron-photoion coincidence time-of-flight mass spectrometry,the photoionization and photodissociation of methyl chloride in the excitation energy range of 13-17 eV were investigated.CH3Cl+ ions in the A2A1 and B2E excited states were generated,both of which were completely dissociative.CH+3 fragments were mainly produced while CH2Cl+ fragment ions were observed as well.By fitting the time-of-flight profile the kinetic energy released distributions of CH3+ during the dissociation of t...