Experimental and theoreticalinvestigations of isomerization reactions of ionized acetone and its dimer
Experimental and theoreticalinvestigations of isomerization reactions of ionized acetone and its dimer
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电离丙酮及其二聚体异构化反应的实验与理论研究
DOI：
10.1039/c1cp22953b
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Asuka Fujii
中科院分区：
文献类型：
--
作者：
Yoshiyuki Matsuda;Kunihito Hoki;Satoshi Maeda;Ken-ichi Hanaue;Keisuke Ohta;Keiji Morokuma;Naohiko Mikami;Asuka Fujii
用最近发展起来的实验和理论相结合的方法研究了丙酮及其二聚体在超音速射流中的电离动力学。在实验中，采用真空-紫外光电离探测方案，用红外预解离光谱研究了中性结构和阳离子结构。采用从头算分子动力学、全局反应路径图、本征反应坐标和人工诱导反应计算等多种理论方法，研究了丙酮单体及其二聚体的单光子电离反应路径。在单光子电离时，二聚体异构化为氢键形式，其中丙酮的烯醇阳离子结合到中性分子上，而这种烯醇化在丙酮单体中是被能量禁止的。二聚体阳离子的烯醇化通过两步质子转移从电离部分的甲基发生，并由二聚体阳离子中的中性部分催化。
Ionization dynamics of acetone and its dimer in supersonic jets is investigated by a combination of experimental and theoretical techniques, both of which have recently been developed. In experiments, the neutral and the cationic structures are explored by infrared predissociation spectroscopy with the vacuum-ultraviolet photoionization detection schemes. Reaction paths following the one-photon ionization of the acetone monomer and its dimer have been studied by the joint use of several theoretical methods including the ab initio molecular dynamics, the global reaction route mapping, the intrinsic reaction coordinate, and the artificial force induced reaction calculations. Upon one-photon ionization, the dimer isomerizes to the H-bonded form, in which the enol cation of acetone is bound to the neutral molecule, while this enolization is energetically forbidden in the acetone monomer. The enolization of the dimer cation occurs through a two-step proton-transfer from the methyl group of the ionized moiety, and is catalyzed by the neutral moiety within the dimer cation.