Investigating the inside of individual molecules by means of Kelvin Probe and Atomic Force Microscopy

最近，具有功能化尖端的单个分子的AFM成像提供了单个分子结构的前所未有的分辨率。除了提供更高的空间分辨率外，功能化尖端的优点是尖端与样品之间的短程相互作用是明确的。这使得对成像过程的前所未有的控制，并允许对潜在的物理过程进行更好的理论描述。这不仅适用于成像，也适用于不同的光谱模式，从3d力映射到开尔文探针力光谱。该项目的目的是通过研究(i)分子内空间分辨率的分子相互作用和（ii）键的极性及其对局部场的响应来利用这些新的可能性。三维力场映射和开尔文探针力谱可以提供最终分辨率的信息，其中频移、局部接触电位差和开尔文抛物线曲率携带补充信息。为了建立实验结果与潜在的物理和化学机制之间的关系，我们的合作伙伴将通过模拟来补充实验。

Recently, AFM imaging of individual molecules with functionalized tips provided an unprecedented resolution of the structure of individual molecules. In addition to providing higher spatial resolution, functionalized tips have the advantage that the short-range interaction between tip and sample is well-defined. This enables an unprecedented control over the imaging process and allows for a much better theoretical description of the underlying physical processes. This does not only apply to imaging, but also to different spectroscopy modes, ranging from 3D-force mapping to Kelvin probe force spectroscopy. The aim of this project is make use of these novel possibilities by studying (i) molecular interactions with intra-molecular spatial resolution and (ii) the polarity of bonds and their response to local fields. Three-dimensional force field mapping and Kelvin probe force spectroscopy shall provide this information at ultimate resolution, for which the frequency shift, local contact potential difference, and the curvature of the Kelvin parabola carry complementary information. To establish the relationship between experimental results and the underlying physical and chemical mechanisms, the experiments will be complemented by simulations from our collaboration partner.