Bro-Jørgensen William, Solomon Gemma C
Department of Chemistry and Nano-Science Center, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark.
NNF Quantum Computing Programme, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark.
J Phys Chem A. 2023 Nov 2;127(43):9003-9012. doi: 10.1021/acs.jpca.3c04631. Epub 2023 Oct 19.
While the use of molecular orbitals (MOs) and their isosurfaces to explain physical phenomena in chemical systems is a time-honored tool, we show that the nodes are an equally important component for understanding the current density through single-molecule junctions. We investigate three different model systems consisting of an alkane, alkene, and even []cumulene and show that we can explain the form of the current density using the MOs of the molecule. Essentially, the MOs define the region in which current can flow and their gradients define the direction in which current flows within that region. We also show that it is possible to simplify the current density for improved understanding by either partitioning the current density into more chemically intuitive parts, such as σ- and π-systems, or by filtering out MOs with negligible contributions to the overall current density. Our work highlights that it is possible to infer a non-equilibrium property (current density) given only equilibrium properties (MOs and their gradients), and this, in turn, grants deeper insight into coherent electron transport.
虽然使用分子轨道（MOs）及其等值面来解释化学系统中的物理现象是一种由来已久的工具，但我们表明，节点对于理解通过单分子结的电流密度同样是重要的组成部分。我们研究了由烷烃、烯烃甚至[累积多烯]组成的三种不同模型系统，并表明我们可以使用分子的分子轨道来解释电流密度的形式。本质上，分子轨道定义了电流可以流动的区域，其梯度定义了该区域内电流流动的方向。我们还表明，通过将电流密度划分为更具化学直观性的部分（如σ键和π键体系），或者通过滤除对总电流密度贡献可忽略不计的分子轨道，有可能简化电流密度以增进理解。我们的工作强调，仅给定平衡性质（分子轨道及其梯度）就有可能推断出非平衡性质（电流密度），这反过来又能更深入地洞察相干电子传输。
