Redefining the dielectric response of nanoconfined liquids: insights from water

Abstract

Recent experiments show that the relative dielectric constant $\epsilon$ of water confined to a film of nanometric thickness reaches a strikingly low value of 2.1, barely above the bulk's 1.8 value for the purely electronic response. We argue that $\epsilon$ is not a well-defined measure for dielectric properties at sub-nanometer scales due to the ambiguous definition of confinement width. Instead we propose the 2D polarizability ${\alpha }_{\perp }$ as the appropriate, well-defined response function whose magnitude can be directly obtained from both measurements and computations. Once the appropriate description is used, understanding the interplay between electronic and ionic contributions becomes critical, contrary to what is widely assumed. This highlights the importance of electronic degrees of freedom in interpreting the dielectric response of polar fluids under nanoconfinement conditions, as revealed by molecular dynamics simulations.

arXiv comment5 pages, 3 figures

References in corpus (12)

• The SIESTA method for ab initio order-N materials simulation
• Efficient index handling of multidimensional periodic boundary conditions
• Anomalously low dielectric constant of confined water
• Thermodynamics, Structure, and Dynamics of Water Confined between Hydrophobic Plates
• Electronic polarizability as the fundamental variable in the dielectric properties of two-dimensional materials
• Computing the dielectric constant of liquid water at constant dielectric displacement
• Water under extreme confinement in graphene: Oscillatory dynamics, structure, and hydration pressure explained as a function of the confinement width
• Note: On the dielectric constant of nanoconfined water
• The nonlocal dielectric response of water in nanoconfinement
• Optimal finite-range atomic basis sets for liquid water and ice
• Continuous melting through a hexatic phase in confined bilayer water
• Molecular Polarizability of Water from the Local Dielectric Response Theory

Cited by in corpus (2)

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