Photoionization study of CH3SCH2Cl formed in the reaction system Cl/Cl2/CH3SCH3
Photoionization study of CH3SCH2Cl formed in the reaction system Cl/Cl2/CH3SCH3
复制标题
Cl/Cl2/CH3SCH3反应体系中CH3SCH2Cl的光电离研究
DOI：
10.1063/1.1349078
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发表时间：
2001
影响因子：
4.4
通讯作者：
C. Yu
中科院分区：
文献类型：
--
作者：
B. Cheng;E. P. Chew;Jen;C. Yu
利用耦合同步加速器作为辐射源的光电离质谱仪测量了CH3SCH2Cl在108 ~ 142 nm波长范围内的光电离效率谱。气体CH3SCH2Cl在放电流反应器中由Cl、Cl2、CH3SCH3在室温下依次反应生成：Cl+CH3SCH3→CH3SCH2+HCl；Cl2 CH3SCH2 +→CH3SCH2Cl + Cl。根据得到的CH3SCH2Cl的PIE谱图，其电离能为（9.077±0.007）eV。基于高斯-2计算，在阈值区附近观察到的CH3SCH2Cl电离可能由单线态CH3SCH2Cl电离到双线态CH3SCH2Cl+；电离能计算值为9.064 eV，与实验值吻合。CH3SCH2的绝热电离能为（6.884±0.008）eV， CH3SCH2+从CH3SCH2Cl生成的外观能为（10.007±0.016）eV；因此，CH3SCH2-Cl键的离解能为（72.0±0.6）kcal mol−1。
A photoionization-efficiency spectrum of CH3SCH2Cl was measured over the wavelength range 108–142 nm by means of a photoionization mass spectrometer coupled to a synchrotron as the source of radiation. Gaseous CH3SCH2Cl was generated in a discharge-flow reactor involving Cl, Cl2, and CH3SCH3 at room temperature via these sequential reactions: Cl+CH3SCH3→CH3SCH2+HCl; CH3SCH2+Cl2→CH3SCH2Cl+Cl. According to the PIE spectrum of CH3SCH2Cl thus obtained, the ionization energy is (9.077±0.007) eV. Based on GAUSSIAN-2 calculations, the observed ionization of CH3SCH2Cl near the threshold region is likely to form from singlet CH3SCH2Cl ionizing to doublet CH3SCH2Cl+; the calculated ionization energy 9.064 eV agrees with the experimental value. The adiabatic ionization energy of CH3SCH2 and appearance energy of CH3SCH2+ from CH3SCH2Cl were determined to be (6.884±0.008) eV and (10.007±0.016) eV, respectively; the dissociation energy of the CH3SCH2–Cl bond is thus derived to be (72.0±0.6) kcal mol−1.