Comparing electronic structure predictions for the ground state dissociation of vinoxy radicals.
Comparing electronic structure predictions for the ground state dissociation of vinoxy radicals.
复制标题
比较乙烯氧基基态解离的电子结构预测。
DOI：
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发表时间：
2007
影响因子：
4.4
通讯作者：
H. Werner
中科院分区：
文献类型：
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作者：
D. I. G. Bennett;L. Butler;H. Werner
本文报道了乙氧基(CH(2)CHO)解离途径的一系列电子结构计算。我们用单、双和微扰三重激发的耦合团簇(CCSD(T))、完全活性空间自洽场(CASSCF)、多参考组态相互作用(MRCI)和带Davidson修正的MRCI(MRCI+Q)计算了该自由基两条单分子解离路径的势垒高度。在CASSCF、MRCI和MRCI+Q水平上研究了态平均对势垒高度的影响。沿反应路径的混合角的变化被计算为导数耦合的量度，并且被发现不足以暗示非绝热的再交叉。我们还给出了一种新的关于基态乙氧基的单分子解离实验数据的分析。特别是对前文中报道的乙氧基自由基内能分布的一个错误进行了修正，并对异构化反应的起始能(势垒高度)对实验的敏感性进行了新的分析。结合这些研究，给出了产物支化比的最终“最坏情况”分析，并发现使用每个计算的过渡态的统计模型不能正确地再现实验数据。
This paper reports a series of electronic structure calculations performed on the dissociation pathways of the vinoxy radical (CH(2)CHO). We use coupled-cluster with single, double, and perturbative triple excitations (CCSD(T)), complete active space self-consistent field (CASSCF), multireference configuration interaction (MRCI), and MRCI with the Davidson correction (MRCI+Q) to calculate the barrier heights of the two unimolecular dissociation pathways of this radical. The effect of state averaging on the barrier heights is investigated at the CASSCF, MRCI, and MRCI+Q levels. The change in mixing angle along the reaction path is calculated as a measure of derivative coupling and found to be insufficient to suggest nonadiabatic recrossing. We also present a new analysis of previous experimental data on the unimolecular dissociation of ground state vinoxy. In particular, an error in the internal energy distribution of vinoxy radicals reported in a previous paper is corrected and a new analysis of the experimental sensitivity to the onset energy (barrier height) for the isomerization reaction is given. Combining these studies, a final "worst case" analysis of the product branching ratio is given and a statistical model using each of the calculated transition states is found to be unable to correctly reproduce the experimental data.