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Title: Vibrational Density of States of Strongly H-Bonded Interfacial Water: Insights from Inelastic Neutron Scattering and Theory

The vibrational dynamics of water and OH sorbed on SnO2 nanoparticles were probed with inelastic neutron scattering and analyzed with the assistance of ab-initio molecular dynamics. The combined analysis points to the existence of very strong hydrogen bonds at the surface with a formation enthalpy twice the average value for liquid water. This unusually large interaction results in (i) decoupling of the hydrated surface from the water system due to an epitaxially-induced screening layer, resulting in an apparent ice-like INS signal at multilayer coverage, (ii) splitting of OH wagging modes that can be used as an experimental indication of the strength of the surface hydrogen bonds, and (iii) high proton exchange rates and high degree of water dissociation at the interface. Our analysis provides general guidance into the tuning of surface hydrophobicity at the molecular level.
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [2]
  1. ORNL
  2. Pennsylvania State University
Publication Date:
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Science; Journal Volume: 118; Journal Issue: 20
Research Org:
Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences (CNMS); Spallation Neutron Source
Sponsoring Org:
SC USDOE - Office of Science (SC)
Country of Publication:
United States