Bastian Björn, Michaelsen Tim, Li Lulu, Ončák Milan, Meyer Jennifer, Zhang Dong H, Wester Roland
Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.
J Phys Chem A. 2020 Mar 12;124(10):1929-1939. doi: 10.1021/acs.jpca.0c00098. Epub 2020 Feb 26.
The dynamics of microhydrated nucleophilic substitution reactions have been studied using crossed beam velocity map imaging experiments and quasiclassical trajectory simulations at different collision energies between 0.3 and 2.6 eV. For F(HO) reacting with CHI, a small fraction of hydrated product ions I(HO) is observed at low collision energies. This product, as well as the dominant I, is formed predominantly through indirect reaction mechanisms. In contrast, a much smaller indirect fraction is determined for the unsolvated reaction. At the largest studied collision energies, the solvated reaction is found to also occur via a direct rebound mechanism. The measured product angular distributions exhibit an overall good agreement with the simulated angular distributions. Besides nucleophilic substitution, also ligand exchange reactions forming F(CHI) and, at high collision energies, proton transfer reactions are detected. The differential scattering images reveal that the Cl(HO) + CHI reaction also proceeds predominantly via indirect reaction mechanisms.
利用交叉分子束速度成像实验和准经典轨迹模拟，在0.3至2.6电子伏特的不同碰撞能量下研究了微水合亲核取代反应的动力学。对于F(HO)与CHI的反应，在低碰撞能量下观察到一小部分水合产物离子I(HO)。该产物以及主要产物I主要通过间接反应机制形成。相比之下，未溶剂化反应的间接反应份额要小得多。在研究的最大碰撞能量下，发现溶剂化反应也通过直接反弹机制发生。测得的产物角分布与模拟角分布总体上吻合良好。除了亲核取代反应外，还检测到形成F(CHI)的配体交换反应以及在高碰撞能量下的质子转移反应。微分散射图像表明，Cl(HO)+CHI反应也主要通过间接反应机制进行。
