Water nano-rings in electric fields

Abstract

Density functional theory (DFT)-based calculations were performed for 36, 72 and 108 water molecules forming twisted ribbon-like nano-ring structures of diameter 1.54, 3.10 and 4.56 nm, respectively. We explore the electric field evolution of the structure, energetics and stability of the water nano-ring structures that are essentially symmetric and non-polar, or less-symmetric and polar, hydrogen-bonded clusters. The results suggest that for fields applied perpendicular to the ring, larger rings are more susceptible to the field influence, while fields applied parallel to the ring quickly transform the ring structures into arbitrary ones, regardless of the ring size. Infrared and Raman spectral analysis of local modes demonstrate the typical vibrational response of water molecules to various H-bonding environments and applied fields, providing a spectroscopic signature that can be used to identify the manifestation of such H-bonded ring networks. Our study underscores the implications of the nano-sized ring water clusters, which have the potential to be exploited in a variety of device applications.