Inverse kinetic isotope effects in the charge transfer reactions of ammonia with rare gas ions.
Inverse kinetic isotope effects in the charge transfer reactions of ammonia with rare gas ions.
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DOI：
10.1039/d1sc01652k
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发表时间：
2021-07-28
期刊：
影响因子：
8.4
通讯作者：
Heazlewood BR
中科院分区：
文献类型：
--
作者：
Tsikritea A;Park K;Bertier P;Loreau J;Softley TP;Heazlewood BR
在缺乏实验数据的情况下，复杂化学环境的模型依赖于预测的反应性质。例如，天体化学模型通常采用俘获理论的变体来估计存在于星际环境中的离子种类的反应性。在这项工作中，我们研究了氨（NH3和ND3）两种同位素物与两种稀有气体离子（Kr+和Ar+）之间与天体化学相关的电荷转移反应。观察到逆动力学同位素效应；ND3比NH3反应快。将这些结果与早先对Xe+的研究结果（Petralia et al., Nat. common）相结合。， 2020, 11,1)，我们注意到动力学同位素效应的大小与稀有气体离子的身份有关。俘获理论模型一贯高估反应速率系数，不能解释观测到的逆动力学同位素效应。在这三种情况下，由高级从头计算构建的反应物和生成物势能面没有表现出任何能量可达的交叉点。借助于一维量子力学模型，我们对这些电荷转移反应体系中逆动力学同位素效应的存在提出了可能的解释。在稀有气体离子与氨分子的电荷转移反应中观察到逆动力学同位素效应。
In the absence of experimental data, models of complex chemical environments rely on predicted reaction properties. Astrochemistry models, for example, typically adopt variants of capture theory to estimate the reactivity of ionic species present in interstellar environments. In this work, we examine astrochemically-relevant charge transfer reactions between two isotopologues of ammonia, NH3 and ND3, and two rare gas ions, Kr+ and Ar+. An inverse kinetic isotope effect is observed; ND3 reacts faster than NH3. Combining these results with findings from an earlier study on Xe+ (Petralia et al., Nat. Commun., 2020, 11, 1), we note that the magnitude of the kinetic isotope effect shows a dependence on the identity of the rare gas ion. Capture theory models consistently overestimate the reaction rate coefficients and cannot account for the observed inverse kinetic isotope effects. In all three cases, the reactant and product potential energy surfaces, constructed from high-level ab initio calculations, do not exhibit any energetically-accessible crossing points. Aided by a one-dimensional quantum-mechanical model, we propose a possible explanation for the presence of inverse kinetic isotope effects in these charge transfer reaction systems. Inverse kinetic isotope effects are observed in the charge transfer reactions of rare gas ions with ammonia molecules.
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影响因子：
15
作者：
Glad, SS;Jensen, F
通讯作者：
Jensen, F
影响因子：
2.8
作者：
DERAI, R;MAUCLAIRE, G;MARX, R
通讯作者：
MARX, R
影响因子：
4.9
作者：
Lis, DC;Roueff, E;Schilke, P
通讯作者：
Schilke, P
DOI：
10.1088/0953-4075/47/13/135204
发表时间：
2014-07-14
影响因子：
1.6
作者：
Loreau, J.;Ryabchenko, S.;Vaeck, N.
通讯作者：
Vaeck, N.
影响因子：
6.5
作者：
Roberts, H;Herbst, E;Millar, TJ
通讯作者：
Millar, TJ