Cartoni Antonella, Catone Daniele, Bolognesi Paola, Satta Mauro, Markus Pal, Avaldi Lorenzo
Dipartimento di Chimica, Sapienza Università di Roma, Pl.e Aldo Moro 5, 00185, Roma, Italy.
Istituto di Struttura della Materia (ISM), Consiglio Nazionale delle Ricerche (CNR), Area della Ricerca di Roma 1, via Salaria Km 29,300, Monterotondo Scalo (RM), 00016, Italy.
Chemistry. 2017 May 17;23(28):6772-6780. doi: 10.1002/chem.201700028. Epub 2017 Apr 5.
In this work an experimental and theoretical study on the formation of HSO ion from the SO +CH and SO +H O ion-molecule reactions at different temperatures is reported. Tunable synchrotron radiation was used to produce the SO ion in excited ro-vibrational levels of the ionic ground state X A and mass spectrometry was employed to identify the product ions. Calculations in the frame of the density functional theory and variational transition state theory were combined to explore the dynamics of the reactions. The experimental results show that HSO is the only product in both reactions. Its yield decreases monotonically with photon energy in the SO +H O reaction, while it decreases at first and then increases in the SO +CH reaction. Theory confirms this trend by calculating the rate constants at different temperatures and explains the results by means of the polar, spin and charge effects as well as structural reorganization occurring in the reaction coordinate. The dynamic behavior observed in these two reactions is of general and fundamental interest. It can also provide some insights on the role of these reactions in astrochemistry as well as in their use as models for bond-activation reactions.
本文报道了一项关于在不同温度下，通过SO + CH和SO + H₂O离子 - 分子反应形成HSO离子的实验和理论研究。利用可调谐同步辐射产生处于离子基态X²Π₁/₂的激发振转能级的SO离子，并采用质谱法鉴定产物离子。结合密度泛函理论框架下的计算和变分过渡态理论，探索反应动力学。实验结果表明，HSO是这两个反应的唯一产物。在SO + H₂O反应中，其产率随光子能量单调下降，而在SO + CH反应中，产率先下降后上升。理论通过计算不同温度下的速率常数证实了这一趋势，并通过反应坐标中发生的极性、自旋和电荷效应以及结构重组来解释结果。在这两个反应中观察到的动力学行为具有普遍和基本的意义。它还可以为这些反应在天体化学中的作用以及它们作为键活化反应模型的应用提供一些见解。
