Coutinho Lúcia H, de A Ribeiro Fabio, Tenorio Bruno N C, Coriani Sonia, Dos Santos Antonio C F, Nicolas Christophe, Milosavljevic Aleksandar R, Bozek John D, Wolff Wania
Physics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil.
Federal Institute of Rio de Janeiro, Rio de Janeiro, 26530-060, Brazil.
Phys Chem Chem Phys. 2021 Dec 15;23(48):27484-27497. doi: 10.1039/d1cp03121j.
We report on single- and double-charge photofragment formation by synchrotron radiation, following C 1s core excitation and ionization and Cl 2p inner excitation and ionization of chlorobenzene, CHCl. From a comparison of experimental near-edge X-ray absorption fine structure spectra and theoretical calculations, the nature of various core and inner shell transitions of the molecule and pure atomic features were identified. To shed light on the normal Auger processes following excitation or ionization of the molecule at the Cl 2p or C 1s sites, we addressed the induced ionic species formation. With energy resolved electron spectra and ion time-of-flight spectra coincidence measurements, the ionic species were correlated with binding energy regions and initial states of vacancies. We explored the formation of the molecular dication CHCl, the analogue benzene dication CH, and the singly charged species produced by single loss of a carbon atom, CHCl. The appearance and intensities of the spectral features associated with these ionic species are shown to be strongly site selective and dependent on the energy ranges of the Auger electron emission. Unexpected intensities for the analogue double charged benzene CH ion were observed with fast Auger electrons. The transitions leading to CHCl were identified from the binding energy representation of high resolution electron energy spectra. Most CHCl ions decay into two singly charged moieties, but intermediate channels are opened leading to other heavy dicationic species, CH and CHCl, the channel leading to the first of these being much more favored than the other.
我们报告了通过同步辐射形成单电荷和双电荷光碎片的情况，这是在氯苯（CHCl）的C 1s芯激发和电离以及Cl 2p内激发和电离之后发生的。通过比较实验近边X射线吸收精细结构光谱和理论计算，确定了分子各种芯层和内壳层跃迁的性质以及纯原子特征。为了阐明分子在Cl 2p或C 1s位点激发或电离后的正常俄歇过程，我们研究了诱导离子物种的形成。通过能量分辨电子光谱和离子飞行时间光谱符合测量，将离子物种与结合能区域和空位的初始状态相关联。我们探索了分子双正离子CHCl、类似的苯双正离子CH以及单失去一个碳原子产生的单电荷物种CHCl的形成。与这些离子物种相关的光谱特征的出现和强度显示出强烈的位点选择性，并取决于俄歇电子发射的能量范围。在快速俄歇电子作用下，观察到了类似双电荷苯CH离子的意外强度。从高分辨率电子能量光谱的结合能表示中确定了导致CHCl的跃迁。大多数CHCl离子衰变为两个单电荷部分，但也打开了通向其他重双正离子物种CH和CHCl的中间通道，通向其中第一个的通道比另一个更受青睐。
