Fluorescence Spectroscopy on Molecules on Surfaces in the Limit of Low Coverages

这个项目的目的是在极低的覆盖率范围内从荧光(FL)和FL激发光谱中获得关于介电表面有机分子的信息。该项目利用了荧光光谱的高光谱分辨率和高灵敏度，旨在使实验甚至达到单分子检测的水平。实验将在明确定义的表面(氯化钠/氯化钾(100))上进行，伴随着表面科学技术的结构控制，如低能电子衍射和扫描隧道显微镜。假设这样的实验将提供以下方面的信息：(A)分子键合到介电表面时的电子/几何状态，(B)不同吸附位置对光谱的影响，以及选择性吸附是否可以减少不均匀线宽的问题，例如在特定的缺陷位置，(C)分子在表面上的扩散、位置迁移和光化学过程的动力学，以及(D)对于小分子聚集体，分子间耦合的量化及其对超辐射发射过程的作用。

The aim of this project is to obtain information on organic molecules on dielectric surfaces from fluorescence (FL) and FL excitation spectroscopy in the limit of very low coverages. The project exploits the high spectral resolution and sensitivity of FL spectroscopy and intends to bring the experiments even to the single molecule detection level. The experiments will be performed on well-defined surfaces (NaCl/KCl(100)) with concomitant structural control by surface science techniques like low energy electron diffraction and scanning tunneling microscopy. It is supposed that such experiments will give information on the following aspects: (a) the electronic/geometric state of a molecule modified upon bonding to a dielectric surface, (b) the influence of different adsorption sites on the optical spectra and the question whether inhomogenous line broadening can be reduced by selective adsorption, e.g. at specific defect sites, (c) the kinetics of diffusion, site migration, and photochemical processes of a molecule on a surface, and finally, (d) for small molecular aggregates, a quantification of intermolecular coupling and its role for superradiant emission processes.