Intramolecular charge transfer processes play an important role in many biological, chemical and physical processes including photosynthesis, redox chemical reactions and electron transfer in molecular electronics. These charge transfer processes are frequently influenced by the dynamics of their molecular or atomic environments, and they are accompanied with energy dissipation into this environment. The detailed understanding of such processes is fundamental for their control and possible exploitation in future technological applications. Most of the experimental studies of the intramolecular charge transfer processes so far have been carried out using time-resolved optical spectroscopies on large molecular ensembles. This hampers detailed understanding of the charge transfer on the single molecular level. Here we build upon the recent progress in scanning probe microscopy, and demonstrate the control of mixed valence state. We report observation of single electron transfer between two ferrocene redox centers within a single molecule and the detection of energy dissipation associated with the single electron transfer.

Charles University Faculty of Mathematics and Physics Ke Karlovu 5 121 16 Prague 2 Czech Republic

Institute of Organic Chemistry and Biochemistry Czech Academy of Sciences Flemingovo nám 2 16610 Prague 6 Czech Republic

Institute of Physics of the Czech Academy of Sciences Cukrovarnická 10 16200 Prague 6 Czech Republic

Regional Centre of Advanced Technologies and Materials Palacký University Šlechtitelů 27 78371 Olomouc Czech Republic

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