最小双氢转移异构体系的精确量子动力学研究

本文对亚乙烯基-乙炔异构化过程开展了高精度量子动力学理论研究. 使用我们建立和发展的高效量子动力学理论方法,进行了大规模的并行计算,其中根据双氢转移的特征定制了高效的基函数. 计算得到了关于A''₁和B''₂对称性的亚乙烯基振动态以及离域态,并与最近的cryo-SEVI实验光谱进行了比对和分析. 计算所得能级与cryo-SEVI光谱实验值吻合很好,两者之间的差异或者与实验测量的误差大小类似,或者不大于30 cm^-1(与亚乙烯基剪形振动模式相关的振动态除外). 本文还揭示和报道了一种特殊的态,称之为异构态,其特征是在亚乙烯基和乙炔区域都有很大的几率分布. 本文首次报道了若干以亚乙烯基特征为主导的振动态,本文的研究将会有助于深入认识双氢转移过程.     

Accurate Quantum Dynamics of the Simplest Isomerization System Involving Double-H Transfer

We perform accurate quantum dynamics calculations on the isomerization of vinylidene-acetylene. Large-scale parallel computations are accomplished by an efficient theoretical scheme developed by our group, in which the basis functions are customized for the double-H transfer process. The \begin{document}$ A_1' $\end{document} and \begin{document}$ B_2'' $\end{document} vinylidene and delocalization states are obtained. The peaks recently observed in the cryo-SEVI spectra are analyzed, and very good agreement for the energy levels is achieved between theory and experiment. The discrepancies of energy levels between our calculations and recent experimental cryo-SEVI spectra are of similar magnitudes to the experimental error bars, or \begin{document}$ \le $\end{document}30 cm\begin{document}$ ^{-1} $\end{document} excluding those involving the excitation of the CCH\begin{document}$ _2 $\end{document} scissor mode. A kind of special state, called the isomerization state, is revealed and reported, which is characterized by large probability densities in both vinylidene and acetylene regions. In addition, several states dominated by vinylidene character are reported for the first time. The present work would contribute to the understanding of the double-H transfer.