Keenan Pieter J, Purkiss Rebecca M, Klamroth Tillmann, Sloan Peter A, Rusimova Kristina R
Department of Physics, University of Bath, Bath, UK.
Centre for Nanoscience and Nanotechnology, University of Bath, Bath, UK.
Nat Commun. 2024 Nov 28;15(1):10322. doi: 10.1038/s41467-024-54677-1.
Programming matter one molecule at a time is a long-standing goal in nanoscience. The atomic resolution of a scanning tunnelling microscope (STM) can give control over the probability of inducing single-outcome single-molecule reactions. Here we show it is possible to measure and influence the outcome of a single-molecule reaction with multiple competing outcomes. By precise injection of electrons from an STM tip, toluene molecules are induced to react with two outcomes: switching to an adjacent site or desorption. Within a voltage range set by the electronic structure of the molecule-surface system, we see that the branching ratio between these two outcomes is dependent on the excess energy the exciting electron carries. Using known values, ab initio DFT calculations and empirical models, we conclude that this excess energy leads to a heating of a common intermediate physisorbed state and gives control over the two outcomes via their energy barriers and prefactors.
一次对一个分子进行编程是纳米科学中长期以来的目标。扫描隧道显微镜（STM）的原子分辨率能够控制引发单结果单分子反应的概率。在此我们表明，对于具有多个竞争结果的单分子反应，测量并影响其反应结果是可能的。通过从STM针尖精确注入电子，甲苯分子会发生两种反应结果：切换到相邻位点或解吸。在由分子 - 表面系统的电子结构设定的电压范围内，我们发现这两种结果之间的分支比取决于激发电子携带的多余能量。利用已知值、从头算密度泛函理论（DFT）计算和经验模型，我们得出结论，这种多余能量会导致一个共同的物理吸附中间态升温，并通过它们的能垒和前因子来控制这两种结果。
