Wu Yanze, Subotnik Joseph E
Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA.
Nat Commun. 2021 Jan 29;12(1):700. doi: 10.1038/s41467-020-20831-8.
Though the concept of Berry force was proposed thirty years ago, little is known about the practical consequences of this force as far as chemical dynamics are concerned. Here, we report that when molecular dynamics pass near a conical intersection, a massive Berry force can appear as a result of even a small amount of spin-orbit coupling (<10 eV), and this Berry force can in turn dramatically change pathway selection. In particular, for a simple radical reaction with two outgoing reaction channels, an exact quantum scattering solution in two dimensions shows that the presence of a significant Berry force can sometimes lead to spin selectivity as large as 100%. Thus, this article opens the door for organic chemists to start designing spintronic devices that use nuclear motion and conical intersections (combined with standard spin-orbit coupling) in order to achieve spin selection. Vice versa, for physical chemists, this article also emphasizes that future semiclassical simulations of intersystem crossing (which have heretofore ignored Berry force) should be corrected to account for the spin polarization that inevitably arises when dynamics pass near conical intersections.
尽管贝里力的概念在三十年前就已提出，但就化学动力学而言，人们对这种力的实际影响知之甚少。在此，我们报告，当分子动力学经过锥形交叉点附近时，即使存在少量的自旋 - 轨道耦合（<10电子伏特），也可能出现巨大的贝里力，而这种贝里力反过来又会显著改变反应路径的选择。特别是，对于一个具有两个出射反应通道的简单自由基反应，二维的精确量子散射解表明，显著的贝里力的存在有时会导致高达100%的自旋选择性。因此，本文为有机化学家开启了一扇门，使他们能够开始设计利用核运动和锥形交叉点（结合标准自旋 - 轨道耦合）来实现自旋选择的自旋电子器件。反之，对于物理化学家来说，本文也强调，未来对系间窜越的半经典模拟（此前一直忽略贝里力）应进行修正，以考虑当动力学经过锥形交叉点附近时不可避免地产生的自旋极化。
