Science and Technology Daily, Beijing, August 26 (Reporter Liu Xia) A research team composed of scientists from the US Department of Energy’s SLAC National Accelerator Laboratory, Stanford University and Stockholm University in Sweden directly observed the "quantum drag" between adjacent water molecules for the first time. This new study reveals the microscopic origin of water's strange properties and helps scientists better understand how water helps proteins function in living organisms.

The research was published in the latest issue of the journal Nature.

  Each water molecule contains one oxygen atom and two hydrogen atoms. The hydrogen bond network between the positively charged hydrogen atoms in one water molecule and the negatively charged oxygen atoms in adjacent water molecules connects them together. This complex The Internet is the "behind-the-scenes hero" with many puzzling properties of water, but researchers have not been able to directly observe how water molecules interact with "neighbors" before.

  Yang Jie, a former SLAC scientist who led this research and now an associate professor at Tsinghua University, explained in an interview with a reporter from Science and Technology Daily that because of the small amplitude and high speed of hydrogen bonds, direct observation in experiments is a big challenge. .

The researchers used the MeV-UED device of the US SLAC National Laboratory to overcome this problem.

MeV-UED is a high-speed "electronic camera" that detects subtle molecular movements through the scattering of high-energy ultra-short electron beams.

  In the latest research, the research team created a liquid water jet with a thickness of 100 nanometers (thickness is only one-thousandth of a human hair) and used infrared lasers to vibrate water molecules.

Subsequently, they used short pulses of high-energy electrons from MeV to bombard the molecule and used this method to obtain a high-resolution snapshot of the atomic structure moving within the molecule.

Each snapshot is a frame, strung together to form a video showing how the network of water molecules reacts to light.

They found that when an excited water molecule starts to vibrate, its hydrogen atoms will draw closer to the oxygen atoms in adjacent water molecules under the action of quantum effects, and then push them away.

  Yang Jie said: "For a long time, scientists have been trying to use spectroscopy to understand the hydrogen bond network, but they can only infer the atomic motion in it indirectly, and have not been able to directly observe it. For the first time, we have directly observed the interaction between these molecules. "Quantum drag". We plan to use this method to further understand the quantum nature of hydrogen bonds and their role in the strange properties of water, as well as the key role these properties of water play in many chemical and biological processes. ."

  Another researcher, Wang Xijie, said: "The latest research has opened a window for related research in the field of water. On this basis, we hope to reveal how water leads to the origin and survival of life on Earth, and provide new information for the development of renewable energy. ."