An increasing number of scanning-probe-based spectroscopic techniques provides access to diverse electronic properties of single molecules. Typically, these experiments can only study a subset of all electronic transitions, which obscures the unambiguous assignment of measured quantities to specific quantum transitions. Here we develop a single-molecule spectroscopy that enables the access to many quantum transitions of different types, including radiative, non-radiative and redox, that is, charge-related, transitions. Our method relies on controlled alternating single-charge attachment and detachment. For read-out, the spin states are mapped to charge states, which we can detect by atomic force microscopy. We can determine the relative energies of ground and excited states of an individual molecule and can prepare the molecule in defined excited states. After a proof-of-principle demonstration of the technique on pentacene, we apply it to PTCDA, the scanning-probe luminescence of which has been interpreted controversially. The method may be used to guide, understand and engineer tip-induced chemical reactions as well as phosphorescence and fluorescence of individual molecules.

越来越多的基于扫描探针的光谱技术提供了了解单分子的不同电子特性的途径。通常，这些实验只能研究所有电子跃迁的一个子集，这模糊了测量量与特定量子跃迁的明确分配。在这里，我们开发了一种单分子光谱学，可以获取许多不同类型的量子跃迁，包括辐射、非辐射和氧化还原（即与电荷相关的跃迁）。我们的方法依赖于受控的交替单电荷附着和分离。为了读出，自旋态被映射到电荷态，我们可以通过原子力显微镜检测到电荷态。我们可以确定单个分子的基态和激发态的相对能量，并可以制备处于定义的激发态的分子。在对并五苯技术进行原理验证演示后，我们将其应用于 PTCDA，其扫描探针发光的解释一直存在争议。该方法可用于指导、理解和设计尖端诱导的化学反应以及单个分子的磷光和荧光。