Electronic, dielectric, and optical properties of two-dimensional and bulk ice: A multiscale simulation study

Abstract

The intercalated water into nanopores exhibits anomalous properties such as an ultralow dielectric constant. Multiscale modeling and simulations are used to investigate the dielectric properties of various crystalline two-dimensional ices and bulk ices. Although the structural properties of two-dimensional (2D) ices have been extensively studied, much less is known about their electronic and optical properties. First, by using density functional theory and density functional perturbation theory (DFPT), we calculate the key electronic, optical, and dielectric properties of 2D ices. Performing DFPT calculations, both the ionic and electronic contributions of the dielectric constant are computed. The in-plane electronic dielectric constant is found to be larger than the out-of-plane dielectric constant for all the studied 2D ices. The in-plane dielectric constant of the electronic response (ε el ) is found to be isotropic for all the studied ices. Second, we determined the dipolar dielectric constant of 2D ices using molecular dynamics simulations at finite temperature. The total out-of-plane dielectric constant is found to be larger than 2 for all the studied 2D ices. Within the framework of the random-phase approximation, the absorption energy ranges for 2D ices are found to be in the ultraviolet spectra. For comparison purposes, we also elucidate the electronic, dielectric, and optical properties of four crystalline ices (ice VIII, ice XI, ice Ic, and ice Ih) and bulk water.

Abnormal Dielectric Constant of Nanoconfined Water between Graphene Layers in the Presence of Salt

“…Recently, the out-of-plane dielectric constant ( ε ⊥ ) of nanoconfined water between two graphene sheets and hexagonal boron nitride was measured using atomic force microscopy. In our previous papers, , using both atomistic simulation and continuum model, we found that ε ⊥ is reduced to 2.1 for confined water in channels with height h ≤ 15 Å. This is due to the reduction of degree of freedom as well as liquid to solid phase transition.…”

Two-dimensional monolayer salt nanostructures can spontaneously aggregate rather than dissolve in dilute aqueous solutions

“…A queous solutions under nanoscale confinement have attracted considerable interest over the past few years, owing to their unusual structural, dynamical, and physicochemical properties (different from those of their bulk counterparts), as well as to their broad significance for nanoscale chemical, biological, and physical systems such as ion channels/ batteries and water desalination [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] . For instance, numerous experiments and molecular dynamics (MD) simulations revealed that nanoconfined water may freeze into various one-dimensional (1D) and two-dimensional (2D) polymorphous and polyamorphous structures at low temperatures 4,8,10,[16][17][18][19][20][21][22][23][24][25][26][27][28][29] . Fast mass transport and high proton conductivity were also observed for water confined inside nanotubes 2,7,30 .…”

Water Nanoconfined in a Hydrophobic Pore: Molecular Dynamics Simulations of Transmembrane Protein 175 and the Influence of Water Models

“…Our results provide mechanistic insights into the behavior of water within a highly nanoconfined pore. This is of direct relevance to the ongoing interest in nanoconfined water as studied either experimentally ( e.g ., refs and ) or computationally ( e.g ., refs and ).…”