Department of Chemistry, Saitama University, Shimo-Okubo 255, Sakura-ku, Saitama 338-8570, Japan.
Molecules. 2020 Feb 17;25(4):882. doi: 10.3390/molecules25040882.
Many chemical reactions of transition metal compounds involve a change in spin state via spin inversion, which is induced by relativistic spin-orbit coupling. In this work, we theoretically study the efficiency of a typical spin-inversion reaction, Fe(CO) + H FeH(CO). Structural and vibrational information on the spin-inversion point, obtained through the spin-coupled Hamiltonian approach, is used to construct three degree-of-freedom potential energy surfaces and to obtain singlet-triplet spin-orbit couplings. Using the developed spin-diabatic potential energy surfaces in reduced dimensions, we perform quantum nonadiabatic transition state wave packet calculations to obtain the cumulative reaction probability. The calculated cumulative reaction probability is found to be significantly larger than that estimated from the one-dimensional surface-hopping probability. This indicates the importance of both multidimensional and nuclear quantum effects in spin inversion for polyatomic chemical reaction systems.
许多过渡金属化合物的化学反应涉及自旋态的变化，这是通过自旋反转来实现的，自旋反转是由相对论自旋-轨道耦合引起的。在这项工作中，我们从理论上研究了典型的自旋反转反应 Fe(CO) + H → FeH(CO) 的效率。自旋反转点的结构和振动信息是通过自旋耦合哈密顿方法获得的，用于构建三个自由度的势能面，并获得单重态-三重态自旋轨道耦合。使用在降维下开发的自旋绝热势能面，我们进行量子非绝热过渡态波包计算，以获得累积反应概率。计算得到的累积反应概率明显大于从一维表面跳跃概率估计得到的概率。这表明在多原子化学反应体系中，自旋反转的多维性和核量子效应的重要性。
