Measuring electric field at molecular level

Illustration of the measuring principle: depending on the local electric potential (voltage) field of a nanostructure on the surface of a sample molecule or atom (bottom), a single electron (red) in a sensor molecule attached to the tip of an atomic force microscope (AFM) jumps from the tip of the microscope to the sensor molecule or not. Credit: Forschungszentrum Jülich

The electric and magnetic fields are the result of the unbalance in the number of electrons and their position in the shells in an atom (the former) and of electrons' spin (the latter). However, what becomes apparent is the sum of contribution from all atoms and this is what is being measured.

At the single atom level the unbalance of electrons is known theoretically but it has never been measured directly. This should not be surprising since it is difficult to isolate an atom....

Now, for the first time researchers at the Forschungscentrum Jülich have managed to measure with a good precision the electric field of a single atom/molecule.

They have used an Atom Force Microscope (AFM) developing a method called scanning quantum dot microscopy and have been able to detect the "aura" that is created by the electrons buzzing around the nuclei. This is not just interesting as a curiosity but has very practical fall out.


In fact, the bindings shaping a molecule (like a protein) depend on "where" electrons are and the electric fields generated. The possibility of measuring with atomic/molecular precision these fields opens up opportunities for work in biomolecules and semiconductors.

Author - Roberto Saracco

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