Effect of fine-tuning pore structures on the dynamics of confined water
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
- Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Geological Sciences
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Physical Sciences Division
Confinement of water in sub-nanometer pores strongly alters its vibrational dynamics from that of bulk water. The effect of confinement can, moreover, be finely tuned by small changes in the size and symmetry of the confining pore. Using inelastic neutron scattering (INS), we recently studied the dynamics of water confined in the channels of beryl and cordierite in which, at low temperatures, water shows similar behavior, indicating an absence of hydrogen bonds acting on the water molecule and a shallow water potential in the direction perpendicular to the channels. In addition, we observed multiple tunneling modes (between 0.66 and 14.7 meV) in the INS spectra of beryl due to transitions between the split ground-state of the water protons. Here, we introduce a study of (i) the effect of pressure on the dynamics of water in beryl, (ii) the dynamics of water in beryl containing alkali metals (which results in changing the orientation of the water molecule in the crystal), and (iii) the dynamics of water in cordierite at low energies. We found a shift in the tunneling and vibrational modes of water in beryl to higher energies at 22 kbar relative to 1 bar. No tunneling modes were observed for water in cordierite and type-II water in beryl. Thus, we conclude that very small differences in the size and structure of the pores and the orientation of the water molecule in these minerals result in changes in the potential of the water protons and drastic changes in the confined water dynamics.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division; Natural Sciences and Engineering Research Council of Canada (NSERC)
- Grant/Contract Number:
- AC05-76RL01830; AC05-00OR22725
- OSTI ID:
- 1545022
- Alternate ID(s):
- OSTI ID: 1518527; OSTI ID: 1523736
- Report Number(s):
- PNNL-SA-142207
- Journal Information:
- Journal of Chemical Physics, Vol. 150, Issue 20; ISSN 0021-9606
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Supercooled water: A polymorphic liquid with a cornucopia of behaviors
|
journal | December 2019 |
Similar Records
Effects of Confinement and Pressure on Vibrational Behavior of Nano-confined Propane
Vibrational states of a water molecule in a nano-cavity of beryl crystal lattice