Novel MD simulation sheds light on mystery of hydrated electron's structure

phys.org | 3/25/2019 | Staff
jenny124124 (Posted by) Level 3
Click For Photo: https://3c1703fe8d.site.internapcdn.net/newman/gfx/news/2019/novelmdsimul.jpg

Extra electrons solvated in liquid water, known as hydrated electrons, were first reported 50 years ago. However, their structure is still not well understood. MARVEL researchers at the University of Zurich, ETH and the Swiss National Supercomputing Center CSCS have now taken a step toward solving the mystery. Their paper, "Dynamics of the Bulk Hydrated Electron from Many Body Wave Function Theory," has been published in Angewandte Chemie.

The e-aq species is difficult to observe directly because it is short-lived and cannot be separated or concentrated. This rules out using direct structural approaches, diffraction or NMR spectroscopy to explore its structure. Though some properties including spectra in UV and IR-regions and the binding energy have been directly observed, the general lack of direct experimental measurements of the structure of the hydrated electron calls for theory.

Modeling - Electron - Approach - Limitations - Approaches

Reliable modeling of the hydrated electron is at least as challenging as the experimental approach, and the limitations of computational approaches applied so far have led to considerable theoretical uncertainty. Researchers have not, for example, been able to agree on whether or not the hydrated electron occupies a cavity. Though most theoretical studies suggest that it does, non-cavity models have also proven accurate. Another point of discussion is linked to the distinguishable surface and bulk structures of the hydrated electron.

In the paper, researchers Vladimir Rybkin and Jan Wilhelm at the University of Zurich and Joost VadeVondele at ETH Zurich and CSCS used the first molecular dynamics simulation of the bulk hydrated electron based on correlated wavefunction theory to provide conclusive evidence in favor of a persistent tetrahedral cavity made up of four water molecules. They also showed that there are no stable non-cavity structures in...
(Excerpt) Read more at: phys.org
Wake Up To Breaking News!
Sign In or Register to comment.

Welcome to Long Room!

Where The World Finds Its News!