The hydrogen bonds that form water molecules are responsible for many of the properties that make water a unique liquid. However, even today scientists do not fully understand the science behind these bonds.
This is because these hydrogen bonds have a very short lifetime and are constantly being formed and broken by the movement of water molecules.
For example, the typical lifetime of a hydrogen bond in liquid water is one millionth of a second. This dynamic behavior makes it difficult to accurately capture and study interactions.
But researchers at the Swiss Federal Institute of Technology Lausanne (EPFL) claim to have developed a new method that will allow scientists to study in detail the electronic and nuclear quantum effects of hydrogen bonds in liquid water.
This new method, called correlated vibrational spectroscopy (CVS), could finally reveal what makes the hydrogen bond network in water such a powerful and mysterious force.
Understanding hydrogen bonds with CVS
Not all water molecules are involved in hydrogen bond network interactions. CVS first identifies and separates interacting and non-interacting molecules. This is done by bombarding water molecules with ultrafast laser pulses.
These quick bursts of light cause the water atoms to make small movements, which then emit visible light. This pattern of light shows how molecules are arranged, and the color of the light shows how atoms move within and between molecules.
“Current spectroscopy measures the scattering of laser light caused by the vibrations of all the molecules in the system, so you have to infer or assume that what you’re seeing is due to the interactions of the molecules of interest. ” says Sylvie Rourke. Study authors and EPFL professors said:
However, for CVS, different types of water molecules exhibit different vibrational patterns. These distinct patterns reveal how a particular molecule moves along a hydrogen bond, allowing researchers to determine the amount of charge shared between the hydrogen and oxygen atoms that form the hydrogen bond. This makes it possible to directly measure things such as the strength of bonds and the strength of bonds.
“This charge sharing is a key feature of the three-dimensional ‘hydrogen bond’ networks that give liquid water its unique properties, but the quantum phenomena at the heart of such networks have so far been elucidated only through theoretical simulations. ” says the study. The author notes.
For the first time, scientists have established an experimental method to investigate this phenomenon and various other aspects of hydrogen bonding in liquid water.
Using CVS goes beyond water
Correlated vibrational spectroscopy (CVS) allows scientists to study the changes that water molecules undergo on a quantum scale. For example, we already know that adding OH⁻ (hydroxide) ions to water makes it basic, and adding protons makes water acidic.
“Using CVS, we can precisely determine how much additional charge the hydroxide ion contributes to the hydrogen bond network (8%) and how much charge the proton receives from the hydrogen bond network (4%). This is a precise measurement that has not previously been possible experimentally, said Misha Flor, lead author of the study and a doctoral student at EPFL. Ta.
However, CVS is not limited to revealing details of the hydrogen bond network of water molecules. The study authors suggest that it could also be used to study other chemicals at the molecular scale.
In the future, we hope that CVS will help scientists solve many mysteries related to other liquids and other chemical and physical systems.
The study was published in the journal Science.
