Towards a quasiphase transition in the single-file chain of water molecules: Simple lattice model

TL;DR

This paper investigates a temperature-driven quasiphase transition in one-dimensional water chains within nanotubes, using quantum calculations, molecular dynamics, and a simple lattice model to explain orientational ordering.

Contribution

It introduces a simple lattice model that captures the temperature-dependent orientational ordering of water molecules in confined one-dimensional systems.

Findings

The model reproduces the quasiphase transition observed experimentally.

Water molecules exhibit persistent orientational order over a wide temperature range.

Both short-range and long-range interactions are crucial for the transition.

Abstract

Recently, X.Ma et al. [Phys. Rev. Lett. 118, 027402 (2017)] have suggested that water molecules encapsulated in (6,5) single-wall carbon nanotube experience a temperature-induced quasiphase transition around 150 K interpreted as changes in the water dipoles orientation. We discuss further this temperature-driven quasiphase transition performing quantum chemical calculations and molecular dynamics simulations and, most importantly, suggesting a simple lattice model to reproduce the properties of the one-dimensionally confined finite arrays of water molecules. The lattice model takes into account not only the short-range and long-range interactions but also the rotations in a narrow tube and the both ingredients provide an explanation for a temperature-driven orientational ordering of the water molecules, which persists within a relatively wide temperature range.