IOM CNR Laboratorio TASC, I-34012 Trieste, Italy.
J Chem Phys. 2011 Oct 14;135(14):144304. doi: 10.1063/1.3646516.
This work provides new experimental and theoretical results about the formation and dissociation of benzene dication. The experiment has been carried out by using a vacuum ultraviolet radiation from a synchrotron source together with a time-of-flight spectrometer and a position sensitive ion detector. Isotopically labeled benzene molecules with a single deuterium atom have been used in order to study the symmetric dissociation of the benzene dication, not well evident in previous experiments. A threshold of 30.1 ± 0.1 eV has been observed for this dissociation reaction. Moreover, the lifetime of the dissociation of the benzene metastable dication producing CH(3)(+) and C(5)H(3)(+) has been obtained as a function of the photon energy, by the use of a Monte Carlo trajectory analysis of the coincidence distributions. The determined lifetime is independent of the photon energy and has an average value of 0.75 ± 0.22 μs. Theoretical calculations of the energy and structure of dissociation product ions have been also performed to provide crucial information about the dynamics of the charge separation reactions following the photoionization event.
这项工作提供了关于苯双阳离子形成和离解的新的实验和理论结果。实验采用同步辐射真空紫外光源，结合飞行时间谱仪和位置灵敏离子探测器进行。为了研究苯双阳离子的对称离解，实验中使用了具有单个氘原子的同位素标记苯分子，这种离解在以前的实验中并不明显。观察到该离解反应的阈能为 30.1 ± 0.1 eV。此外，通过对符合分布的蒙特卡罗轨迹分析，获得了产生 CH(3)(+)和 C(5)H(3)(+)的苯亚稳态双阳离子离解的寿命作为光子能量的函数。确定的寿命与光子能量无关，平均值为 0.75 ± 0.22 μs。还进行了离解产物离子的能量和结构的理论计算，为光致电离事件后电荷分离反应的动力学提供了关键信息。
