Electron-impact ionization of hydrogen chloride
Electron-impact ionization of hydrogen chloride
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DOI：
10.1039/b007494m
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发表时间：
2001-01-01
影响因子：
3.3
通讯作者：
Price, SD
中科院分区：
文献类型：
--
作者：
Harper, S;Calandra, P;Price, SD
根据同时记录的质量和二维离子-离子符合光谱，确定了从氯化氢分子形成 Cl+、Cl2+ 和 H+ 的相对部分电离截面，作为 30 至 200 eV 电离电子能量的函数。前驱体特定横截面已得出，其量化了每个电离水平对每个碎片离子产量的贡献，并且多电荷 HCl 碎片反应中释放的动能已用于获得双电荷和三电荷态的热力学信息。分析表明，在 100 eV 电子能量下，双电离贡献了总离子产率的 12%，在 50 eV 电子能量下，双电离贡献了 3%。在 100 eV 时，大约 41% 的双电离事件导致 HCl2+ 因失去 H 原子而衰变形成 Cl2+，这与电荷分离离解的频率 (52%) 相当。 Cl2+ 的形成阈值为 46.8 +/- 1.5 eV，并被分配给 c (5)Sigma (-) 阳离子状态。观察到的形成长寿命双阳离子 (HCl2+) 的阈值与双阳离子基态的数量一致，并且该状态的较高振动水平似乎有助于 H+ + Cl+ 离子对的产生。亚稳态 HCl2+ 的形成对离子产率的贡献最大为 0.6%。未检测到长寿命 HCl3+ 离子，但解离三重电离约占 200 eV 离子产率的 0.7%。我们估计 HCl3+ 的最低解离态位于中性分子基态以上 72 +/- 2 eV 处。
Relative partial ionization cross sections for the formation of Cl+, Cl2+ and H+ from the hydrogen chloride molecule have been determined, from simultaneously recorded mass and two-dimensional ion-ion coincidence spectra, as a function of the ionizing electron energy from 30 to 200 eV. Precursor specific cross sections have been derived which quantify the contribution to the yield of each fragment ion from each level of ionization and the kinetic energy released in the fragmentation reactions of multiply charged HCl has been used to obtain thermodynamic information on the doubly and triply charged states. Analysis shows that at 100 eV electron energy double ionization contributes 12% of the total ion yield and 3% at 50 eV. At 100 eV the decay of HCl2+ by the loss of an H atom to form Cl2+ is a result of approximately 41% of the double ionization events, comparable to the frequency of charge separating dissociation (52%). The formation of Cl2+ has a threshold of 46.8 +/- 1.5 eV and is assigned to population of the c (5)Sigma (-) dication state. The observed threshold for forming long-lived dications (HCl2+) is consistent with the population of the ground state of the dication, and higher vibrational levels of this state appear to contribute to the yield of H+ + Cl+ ion pairs. The formation of metastable HCl2+ contributes a maximum of 0.6% to the ion yield. Long-lived HCl3+ ions are not detected but dissociative triple ionization makes up approximately 0.7% of the ion yield at 200 eV. We estimate the lowest lying dissociative state of HCl3+ lies at 72 +/- 2 eV above the ground state of the neutral molecule.