Attosecond spectroscopy of size-resolved water clusters
July 12, 2022(Published in Nature)
Virtually all vital chemical processes take place in aqueous solutions. In such processes, a decisive role is played by electrons that are exchanged between different atoms and molecules and thus, for instance, create or break chemical bonds. The details of how that happens, however, are difficult to investigate as those electrons move very fast. Researchers at ETH Zurich led by Hans Jakob Wörner, professor of physical chemistry, in collaboration with colleagues at Lawrence Berkeley National Laboratory (USA) have now succeeded in studying the dynamics of electrons in clusters made of water molecules with a time resolution of just a few attoseconds. Their results recently appeared as an advance publication in the scientific journal Nature.
In their experiments, the scientists studied how water clusters are ionised by a short laser pulse in the extreme ultraviolet. To that end, clusters are first created by squeezing water vapour through a tiny nozzle under high pressure. The energy of the extreme ultraviolet photons of the laser pulse then cause one electron of the cluster to be released. This leads to a vacancy also known as a “hole”.
The release of the electron, however, does not occur immediately after the arrival of the pulse, but rather after a short delay. That delay depends on how the electron hole is distributed across the molecules of the cluster. “Up to now, the distribution of the hole could only be calculated theoretically, as the delay is far too short to be measured with traditional methods”, explains Xiaochun Gong, the post-doc who was in charge of the project.
For more details see the ETH News.
<<