After examining the strength of the most common element in the universe, scientists have gained a deeper knowledge of hydrogen bonds in a single molecule.

Researchers at the University of Basel’s Swiss Nanoscience Institute have used an atomic force microscope to show how molecules and sections of macromolecules are connected to one another through hydrogen atoms.

These interactions are responsible for specific properties of proteins or nucleic acids.

The research has paved the way for new techniques to identify 3D molecules, including nucleic acids or polymers through the observation of hydrogen atoms.

However, scientists have been unable to conduct a spectroscopic or electron microscopic analysis of hydrogen and hydrogen bonds in single molecules.

Until now examinations using atomic force microscopy have not produced clear results.

The researchers used compounds whose configuration resemble a propeller because they arrange themselves on a surface in a way so that two hydrogen atoms always point upwards. The tip of the atomic force microscope is functionalized with carbon monoxide and is brought close enough to the hydrogen atoms, forming hydrogen bonds that can now be examined.

Hydrogen bonds are considered weaker than chemical bonds but stronger than intermolecular van der Waals interactions—forces driven by induced electrical interactions between two or more atoms or molecules that are very close to each other.

The measured forces and distances between the oxygen atoms at the tip of the atomic force microscope and the propellane’s hydrogen atoms show that the interaction clearly involves hydrogen bonds and the measurements show that the weaker van der Waals forces and the stronger ionic bonds can be excluded.