Local Atomic and Electronic Structure

该项目的目的是在原子尺度上研究分子在氧化物表面的吸附、自组装和共价网络形成。为此，采用低温扫描隧道显微镜和超高真空非接触式原子力显微镜。funCOS分子工具箱中的分子将沉积在CoO、Co3O4和MgO表面，并在原子尺度上研究它们的吸附行为和自组装。FunCOS 1将通过选择分子侧基和激活尚未在氧化物上研究过的分子间结合方案，进一步发展分子自组装的控制。羧基和氨基之间的氢键，卤素键和氧化物表面形成的金属配位网络是主要的兴趣。研究了官能团和金属附原子在氧化物上的热稳定性。与官能团活化相关的是分子表面反应引起的分子-底物相互作用的其他修饰。一个突出的例子是在第一个funCOS资助期间在MgO和CoO上发现的游离基卟啉的自-自金属化。有迹象表明，自金属化过程中释放的氢可能引起CoO的结构变化，影响分子的吸附和自组装。因此，该项目将详细研究氧化钴和氧化镁表面的氢和羟基的性质。这将通过分别通过原子源或通过水的解离有意地提供氢原子或羟基来实现。此外，分子之间的脱氢或脱卤均偶联，以及利用金属有机键形成的共价网络将在氧化物表面上进行研究。功能化氧化表面的潜力将通过研究原子尺度缺陷的作用来探索，自然发生或由离子或电子照射产生，在触发甚至催化适当的表面反应。最后，扫描探针光谱将用于确定分子系统的电子性质。利用扫描隧道光谱研究了分子边界轨道和分子-氧化物界面的能级排列。通过开尔文探针力显微镜将研究分子层内和分子-氧化物界面的局部接触电位差。这个项目的活动很好地融入了科科司研究单位的活动。局部观点补充了其他funCOS项目中采用的非局部电子能谱和散射方法的分子吸附研究。与funcos6合作，将设计扫描探针结果的理论模型。

The project funCOS 1 aims at investigating molecular adsorption, self-assembly and covalent network formation on oxide surfaces at the atomic scale. For that it employs low-temperature Scanning Tunneling Microscopy and non-contact Atomic Force Microscopy in ultra-high vacuum.Molecules from the funCOS molecular toolbox will be deposited on CoO, Co3O4, and MgO surfaces and their adsorption behavior and self-assembly will be studied at the atomic scale. FunCOS 1 will further develop the steering of molecular self-assembly by the choice of molecular side-groups and by activating intermolecular binding schemes that are not yet investigated on oxides. The hydrogen bonding between carboxyl and amino groups, halogen bonding and the formation metal-coordinated networks on oxide surfaces is of prime interest. The thermal stability of the functional groups and metal adatoms on oxides will be investigated.Related to the activation of functional groups are other modifications of the molecule-substrate interaction introduced by on-surface reactions of the molecules. A prominent example is the self-self-metalation of free-base porphyrins found on MgO and CoO during the first funCOS funding period. There are hints that hydrogen released during self-metalation might induce structural changes on CoO influencing molecular adsorption and self-assembly. This project will therefore study in detail the properties of hydrogen and hydroxyls on cobalt oxide and magnesium oxide surfaces. This will be achieved by intentionally supplying hydrogen atoms or hydroxyls by an atom source or by the dissociation of water respectively. Further, dehydrogenative or dehalogenated homocoupling between molecules, and the formation of covalent networks employing metalorganic bonds will be studied on oxide surfaces. The potential of functionalizing oxide surfaces will be explored by investigating the role of atomic-scale defects, naturally occurring or created by ion or electron irradiation, in triggering or even catalyzing appropriate surface reactions. Finally, scanning probe spectroscopies will be used to determine the electronic properties of the molecular systems. By Scanning Tunneling Spectroscopy molecular frontier orbitals and the energy-level alignment at the molecule-oxide interface will be studied. By Kelvin Probe Force Microscopy local contact potential differences within molecular layers and across the molecule-oxide interface will be investigated.The activities of this project are well embedded within the activities of the funCOS research unit. The local view complements the studies of molecular adsorption by non-local electron spectroscopy and scattering methods employed in the other funCOS projects. In collaboration with funCOS 6 a theoretical modeling of the scanning probe results will be devised.