Integrated Molecular Simulations and Neutron Scattering Reveal the Energetics of Hydrogen Bonds at a Mineral Surface
Inelastic neutron scattering (INS) studies of water sorbed on tin oxide (SnO2, cassiterite) nanoparticle surfaces at low humidity and ab initio molecular dynamics (AIMD) simulations were independently analyzed to extract the vibrational density of states (VDOS) of water and OH groups, showing the effects of water dissocation and very strong intra-surface H-bonds.
Significance and Impact
The vibrational peaks in the INS spectrum from H2O and OH vibrational dynamics in the 0-200 meV range, and OH stretching modes at higher energies can be uniquely assigned to specific surface species motions using AIMD simulations.
- INS spectra were collected on the SEQUOIA spectrometer at ORNL’s Spallation Neutron Source
- AIMD simulations were conducted using ORNL’s JAGUAR supercomputer