Static Distortion Waves in Epitaxial Non-Commensurate Adlayers

外延非等比吸附层中的静态畸变波

• 批准号: 430865859
• 负责人: Professor Dr. Torsten Fritz
• 金额: --
• 依托单位: Lehrstuhl für Angewandte Physik / Festkörperphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/430865859?language=en
• 关键词: Static; Distortion; Waves; Epitaxial; Non

The main scientific goal of our proposal is to demonstrate that static distortion waves (SDWs) play a universal role in the structure formation of organic adsorbates. These represent rather flexible adsorbate lattices caused by the weak interaction forces between molecules, namely van der Waals forces and – if suitable atoms are contained in the molecules – hydrogen bonds. To that end, we will investigate self-assembled monolayers of a variety of molecules with several distinct aspects, grown on graphitic and metallic substrates. A unique method is proposed to quantitatively assess interactions in two-dimensional non-commensurate molecular aggregates (which exhibit a broad distribution of nearest-neighbor distances) via the observation of SDWs by means of low-temperature STM accompanied by distortion-corrected LEED measurements. To rationalize the experimental results, relaxation simulations (away from the average lattice) will be performed. The parameter-free intra- and interlayer interaction energy landscapes needed for those simulations will be obtained from state-of-the-art dispersion-corrected DFT calculations.From a computational/theoretical point of view, SDWs are particularly interesting for multiple reasons. Importantly, in SDW systems molecules adsorb on a variety of different adsorption sites. To describe SDWs, it is thus insufficient to only reproduce quantitatively the energetically most favorable adsorption site. Rather, it is imperative to obtain a good representation of a large part of the potential energy surfaces describing the molecule-substrate and molecule-molecule interactions. As a first step, we will map those interactions separately by discretizing and “brute-forcing” the potential energy surfaces. Going beyond the established approach, we will test a number of different computational methods for the evaluation of molecule-substrate and molecule-molecule interactions. As a second step, we will speed up the evaluation of the potential energy surfaces using machine learning methods. Specifically, we will rely on Gaussian Process Regression (GPR) to determine interactions at the interface of organic molecules with inorganic substrates. By combining the experimental and calculation results, quantitative information on the strength of the intermolecular interactions will be obtained.

我们建议的主要科学目标是证明静态失真波（SDW）在有机吸附物的结构形成中起着普遍的作用。这些代表了由分子之间的弱相互作用力（即范德华力）引起的相当柔性的吸附晶格，如果分子中包含合适的原子，则是氢键。为此，我们将研究各种分子的自组装单层，这些单分子具有多个不同的方面，它们在图形和金属底物上生长。提出了一种独特的方法，以通过观察SDW的观察，通过通过失真校正后的LEED测量值来实现SDW，通过观察SDW的观察，通过观察到SDW来定量评估二维非固定分子聚集体（表现出广泛的最近邻距距离的广泛分布）。为了合理化实验结果，将进行松弛模拟（远离平均晶格）。这些模拟所需的无参数内和层间相互作用的能量景观将从最新的分散校正的DFT计算中获得。从计算/理论观点来看，SDWS由于多种原因而尤其有趣。重要的是，在SDW系统分子中吸附在各种不同的吸附位点上。为了描述SDW，因此不足以定量地重现本质上最有利的吸附位点。相反，必须获得描述分子底物和分子 - 分子相互作用的大部分势能表面的良好表示。作为第一步，我们将通过离散和“蛮力”势能表面分别绘制这些相互作用。除了既定方法之外，我们将测试多种不同的计算方法，以评估分子 - 基底和分子 - 分子相互作用。作为第二步，我们将使用机器学习方法加快对势能表面的评估。具体而言，我们将依靠高斯过程回归（GPR）来确定有机分子与无机底物的界面上的相互作用。通过结合实验和计算结果，将获得有关分子间相互作用强度的定量信息。