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.

我们提案的主要科学目标是证明静态畸变波（SDW）在有机吸附物的结构形成中发挥普遍作用，这些代表了由分子之间的弱相互作用力（即范德华力和）引起的相当灵活的吸附物晶格。 – 如果分子中包含合适的原子 – 氢键 为此，我们将研究在石墨和金属基底上生长的具有几个不同方面的各种分子的自组装单层。通过低温 STM 以及畸变校正 LEED 测量来观察 SDW，评估二维非等比分子聚集体（表现出广泛的最近邻距离分布）中的相互作用。将从最先进的色散校正中获得这些模拟所需的无参数层内和层间相互作用能量景观。 DFT 计算。从计算/理论的角度来看，SDW 由于多种原因而特别有趣。重要的是，在 SDW 系统中，分子吸附在各种不同的吸附位点上，因此仅定量地再现最活跃的吸附位点是不够的。相反，必须获得描述分子-基质和分子-分子相互作用的大部分势能的良好表示。作为第一步，我们将通过离散化分别绘制这些相互作用。超越现有的方法，我们将测试许多不同的计算方法来评估分子-基质和分子-分子相互作用。具体来说，我们将依靠高斯过程回归（GPR）通过结合实验和计算结果来确定有机分子与无机基材界面的相互作用，从而获得有关势能表面强度的定量信息。分子间相互作用将获得。