Forces on nuclei moving on autoionizing molecular potential energy surfaces.
Forces on nuclei moving on autoionizing molecular potential energy surfaces.
复制标题
在自电离分子势能表面上运动的原子核上的力。
DOI：
10.1063/1.4973559
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
N. Moiseyev
中科院分区：
文献类型：
--
作者：
N. Moiseyev
分子系统的自电离发生在双原子分子和小的生化系统中。量子化学程序包允许计算复杂势能面(CPES)。CPES的虚部与自电离衰减率有关，自电离衰减率是分子结构的函数。在Born-Oppenheimer近似的框架内，分子动力学模拟需要定义一个力场。当自电离发生时，计算生物系统中原子核上的力的能力似乎依赖于对RNA和DNA中辐射损伤的理解，这些辐射损伤是由具有长德布罗意波长的慢速电子的释放引起的。这项工作涉及对在CPES上运动的原子核的真实力的计算。通过对Madelung以前使用的含时薛定谔方程的变换，我们证明了在CPES上运动的原子核上的经典作用力与CPES实部的梯度相关。结果表明，尽管检测到亚稳分子的几率呈指数衰减，但对亚稳分子原子核的作用力与时间无关。当ℏ=0时，由变换后的薛定谔方程得到经典作用力，并将薛定谔方程简化为经典(牛顿)运动方程。由于自电离过程，无论原子核在什么势能面上移动(母体CPES或产物真实PESS)，原子核上的力都会随着时间的变化而变化。
Autoionization of molecular systems occurs in diatomic molecules and in small biochemical systems. Quantum chemistry packages enable calculation of complex potential energy surfaces (CPESs). The imaginary part of the CPES is associated with the autoionization decay rate, which is a function of the molecular structure. Molecular dynamics simulations, within the framework of the Born-Oppenheimer approximation, require the definition of a force field. The ability to calculate the forces on the nuclei in bio-systems when autoionization takes place seems to rely on an understanding of radiative damages in RNA and DNA arising from the release of slow moving electrons which have long de Broglie wavelengths. This work addresses calculation of the real forces on the nuclei moving on the CPES. By using the transformation of the time-dependent Schrödinger equation, previously used by Madelung, we proved that the classical forces on nuclei moving on the CPES correlated with the gradient of the real part of the CPES. It was proved that the force on the nuclei of the metastable molecules is time independent although the probability to detect metastable molecules exponentially decays. The classical force is obtained from the transformed Schrödinger equation when ℏ=0 and the Schrödinger equation is reduced to the classical (Newtonian) equations of motion. The forces on the nuclei regardless on what potential energy surface they move (parent CPES or product real PESs) vary in time due to the autoionization process.