 Molecules can be charged by adding or removing single electrons. When on a support, the atoms in the support will react towards this additional charge. This effect has important implications for future devices based on electron transfer between molecules. IBM researchers asked a simple question. How to quantify the relaxation of nuclei in a molecular system? To accomplish such a goal, an atomic force microscope operated at low temperature and ultra-high vacuum is employed. The metallic tip of the microscope is used to attach or detach single electrons to the molecule, hence charging it. In the experiment, the team observed that a molecule is charged and discharged at different applied voltages. The difference of these voltages is linked to the reorganization energy. It is the energy gained because of the change in the positions of the atoms upon charging. The quantification of the reorganization energy was the aim of the researchers. However, measuring the voltage difference in a single charging and discharging experiment is not enough to quantify the reorganization energy, primarily because of the randomness involved in an individual electron tunneling process. Hence a new approach was needed. Reporting today in Nature Nanotechnology, the IBM Research Xerox team demonstrates a methodology to measure the reorganization energy. The method is based on using the atomic force microscope as a current meter, measuring single electron events corresponding to particular charged states of a single molecule on an insulating substrate. In this experiment, the average time needed to attach and detach single charges as a function of voltage applied is extracted. This allows electronic characterization of nanometric systems on insulators as well as the measurement of their reorganization energy.