Scientists of the National SLAC Accelerator Lab at the US Department of Energy, Stanford University and Stockholm University in Sweden for the first time made direct observation of how hydrogen atoms in water molecules interact with adjacent molecules when the laser light is excited. This is reported in an article published in the journal Nature.
Each water molecule contains one oxygen atom and two hydrogen atoms, and a network of hydrogen bonds between positively charged hydrogen atoms in one molecule and adversely charged oxygen atoms in adjacent molecules holds the molecule together. The network of hydrogen bonds determines the mysterious properties of water, but until recently, researchers could not directly observe the effects arising from the interaction of water molecules with their neighbors at the atomic level.
A new study for the first time directly demonstrates that the reaction of a network of hydrogen bonds on an energy pulse critically depends on the quantum-mechanical nature of how hydrogen atoms are distributed in space. The problem was solved using the SLAC MEV-UED, high-speed “electronic chamber”, which fixes the low-speed movements of molecules through the dispersion of a powerful beam of electrons from the sample.
Scientists have created a jet of liquid water with a thickness of 100 nanometers and forced the molecules to vibrate with the help of infrared laser light. Then they sent short pulses of high-energy electrons on molecules. As a result, snapshots of the changing atomic structure of high-resolution molecules were obtained. It turned out that when the excited water molecule begins to vibrate, its hydrogen atom attracts the oxygen atoms of neighboring water molecules closer, before pushing them with a newly acquired force, expanding the space between molecules.