论文标题
通过微型典型方法从Instanton理论中的速率常数
Rate constants from instanton theory via a microcanonical approach
论文作者
论文摘要
Microcanonical Instanton理论提供了为化学反应提供速率常数，包括整个温度范围内原子的量子隧穿。我们讨论不同的速率表达式，这需要计算Instantons的稳定性参数。在实际应用中，获得这些稳定参数的传统方式在数值上是不稳定的。我们提供了三种替代算法，以获得不可分离系统的稳定性参数，即垂直于Instanton路径夫妇沿路径运动的振动模式的系统。我们在两个分子系统上显示了算法的适用性：H $ _2 $ + OH $ \ rightArrow $ h $ _2 $ _2 $ o + H使用拟合的势能表面和HNCO + H $ \ rightRow $ nh $ _2 $ CO，使用从密度功能计算中获得的潜在获得的潜在获得。
Microcanonical instanton theory offers the promise of providing rate constants for chemical reactions including quantum tunneling of atoms over the whole temperature range. We discuss different rate expressions, which require the calculation of stability parameters of the instantons. The traditional way of obtaining these stability parameters is shown to be numerically unstable in practical applications. We provide three alternative algorithms to obtain such stability parameters for non-separable systems, i.e., systems in which the vibrational modes perpendicular to the instanton path couple to movement along the path. We show the applicability of our algorithms on two molecular systems: H$_2$ + OH $\rightarrow$ H$_2$O + H using a fitted potential energy surface and HNCO + H $\rightarrow$ NH$_2$CO using a potential obtained on-the-fly from density functional calculations.
