| Autor: |
Morawietz T; Department of Chemistry , Stanford University , Stanford , California 94305 , United States., Urbina AS; Department of Chemistry , Purdue University , West Lafayette , Indiana 47907 , United States., Wise PK; Department of Chemistry , Purdue University , West Lafayette , Indiana 47907 , United States., Wu X; College of Marine Science and Technology , China University of Geosciences , Wuhan 430074 , China., Lu W; College of Marine Science and Technology , China University of Geosciences , Wuhan 430074 , China., Ben-Amotz D; Department of Chemistry , Purdue University , West Lafayette , Indiana 47907 , United States., Markland TE; Department of Chemistry , Stanford University , Stanford , California 94305 , United States. |
| Abstrakt: |
Molecules with an excess number of hydrogen-bonding partners play a crucial role in fundamental chemical processes, ranging from anomalous diffusion in supercooled water to transport of aqueous proton defects and ordering of water around hydrophobic solutes. Here we show that overcoordinated hydrogen-bond environments can be identified in both the ambient and supercooled regimes of liquid water by combining experimental Raman multivariate curve resolution measurements and machine learning accelerated quantum simulations. In particular, we find that OH groups appearing in spectral regions usually associated with non-hydrogen-bonded species actually correspond to hydrogen bonds formed in overcoordinated environments. We further show that only these species exhibit a turnover in population as a function of temperature, which is robust and persists under both constant pressure and density conditions. This work thus provides a new tool to identify, interpret, and elucidate the spectral signatures of crowded hydrogen-bond networks. |
