Zhou Jiaqi, Belina Michal, Jia Shaokui, Xue Xiaorui, Hao Xintai, Ren Xueguang, Slavíček Petr
School of Physics, Xi'an Jiaotong University, Xi'an710049, China.
Department of Physical Chemistry, University of Chemistry and Technology,Technická 5, 16628Prague 6, Czech Republic.
J Phys Chem Lett. 2022 Nov 17;13(45):10603-10611. doi: 10.1021/acs.jpclett.2c02560. Epub 2022 Nov 9.
We investigate the ultrafast energy and charge transfer processes between ammonia molecules following ionization reactions initiated by electron impact. Exploring ionization-induced processes in molecular clusters provides us with a detailed insight into the dynamics using experiments in the energy domain. We ionize the ammonia dimer with 200 eV electrons and apply the fragment ions coincident momentum spectroscopy and nonadiabatic molecular dynamics simulations. We identify two mechanisms leading to the doubly charged ammonia dimer. In the first one, a single molecule is ionized. This initiates an ultrafast proton transfer process, leading to the formation of the NH + NH pair. Alternatively, a dimer with a delocalized charge is formed dominantly via the intermolecular Coulombic decay, forming the NH·NH dication. This dication further dissociates into two NH cations. The calculations have reproduced the measured kinetic energy release of the ion pairs and revealed the dynamical processes following the double ionization.
我们研究了电子碰撞引发的电离反应后氨分子之间的超快能量和电荷转移过程。探索分子簇中的电离诱导过程，通过能量域实验为我们提供了对动力学的详细洞察。我们用200 eV电子使氨二聚体电离，并应用碎片离子符合动量光谱和非绝热分子动力学模拟。我们确定了导致双电荷氨二聚体的两种机制。第一种机制是单个分子被电离。这引发了超快质子转移过程，导致形成NH⁺NH对。或者，主要通过分子间库仑衰变形成具有离域电荷的二聚体，形成NH·NH双阳离子。该双阳离子进一步解离为两个NH阳离子。计算结果再现了测量的离子对动能释放，并揭示了双电离后的动力学过程。
