 What we want to measure in our experiment is how the structure of a molecule changes when we add its charge state, so that is when we add or remove an electron. And this is very important in many organisms, for example the charge states of chlorophyll and hemoglobin, which are important for the charge and energy transfer in our body and in plants. And what we do here is we resolve on the atomic scale the structure changes of a molecule when we remove or add a single elementary charge, that is one electron. This is the instrument that we used, it's an ultra high vacuum, low temperature atomic force microscope. This is the cantilever that we have in our system, which is a Q plus sensor. With that we functionalize the tip of our sensor with a CO molecule and this allows us to attain two capabilities of AFM, one which is the atomic resolution and the other which is the fact that we can attach or remove electrons from a molecule at will. And by coupling these two capabilities we can see how the structure of a molecule changes upon changing its charge state. Here you have porphyne, the parent compound of hemoglobin and chlorophyll and here you see it in three different charge states. The neutral with one attached to the electron and with two attached to the electrons. With our work and our new technique we gain a fundamental understanding on the atomic scale of how single electrons change the structure of molecules. And this is important on the one hand in living organisms as we explained and on the other hand for new applications of molecules in molecular devices and organic photovoltaic cells for example.