标题： 非绝热环聚合物瞬态速率理论：广义分界面方法 显示英文标题

标题： Nonadiabatic ring-polymer instanton rate theory: a generalised dividing-surface approach

摘要： 构建一个在任意电子耦合值下都准确的非绝热速率理论近似方法，长期以来一直是理论化学中的一个重大挑战。 环聚合物瞬子理论提供了一种非常有前景的解决此问题的方法，因为它们可以通过半经典近似严格推导出来，并且能够以接近经典计算的成本捕捉核量子效应（如隧穿和零点能量）。 在玻恩-奥本海默近似中已经存在一个成功的瞬子速率理论，其中最优隧穿路径位于单一绝热表面上。 基于费米黄金规则，在两个弱耦合的二绝热面内也已开发出一种相关的瞬子理论，用于非绝热反应。 然而，许多化学反应并不满足这两个极限条件。 通过采用可调的分割面来测量核坐标以及电子态之间的通量，我们发展了一种广义的非绝热瞬子速率理论，连接了这两种极限。 该理论对于所研究的系统很好地近似了量子力学精确的速率，并且还为非绝热反应提供了新颖的机制视角。 显示英文摘要

摘要： Constructing an accurate approximation to nonadiabatic rate theory which is valid for arbitrary values of the electronic coupling has been a long-standing challenge in theoretical chemistry. Ring-polymer instanton theories offer a very promising approach to solve this problem, since they can be rigorously derived using semiclassical approximations and can capture nuclear quantum effects such as tunnelling and zero-point energy at a cost similar to that of a classical calculation. A successful instanton rate theory already exists within the Born--Oppenheimer approximation, for which the optimal tunnelling pathway is located on a single adiabatic surface. A related instanton theory has also been developed for nonadiabatic reactions using two weakly-coupled diabatic surfaces within the framework of Fermi's golden rule. However, many chemical reactions do not satisfy the conditions of either limit. By employing a tunable dividing surface which measures the flux both along nuclear coordinates as well as between electronic states, we develop a generalised nonadiabatic instanton rate theory that bridges between these two limits. The resulting theory approximates the quantum-mechanically exact rates well for the systems studied and, in addition, offers a novel mechanistic perspective on nonadiabatic reactions.