2016/11/21 by Ji Chen, Andrea Zen, Jan Gerit Brandenburg +2 · 58 citations
Chemistry · Earth and Planetary Sciences · Mathematics · Physics and Astronomy · #Advanced Chemical Physics Studies #Chemistry #Condensed matter physics #Degenerate energy levels #Density functional theory #Diffusion Monte Carlo #Enthalpy #Geometry #Markov chain Monte Carlo #Materials science #Mathematics #Monte Carlo method #Monte Carlo molecular modeling #Phase (matter) #Physics #Quantum Monte Carlo #Quantum mechanics #Quantum, superfluid, helium dynamics #Square (algebra) #Statistical physics #Statistics #Thermodynamics #cond-mat.mtrl-sci #nanoparticles nucleation surface interactions #physics.chem-ph #physics.comp-ph
paper · pdf · doi:10.1103/physrevb.94.220102
published in Physical review. B./Physical review. B 94(22) (American Physical Society)
arxiv created 2016/11/21 · openalex publication_date 2016/12/06 · arxiv updated 2016/12/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Recent experiments on ice formed by water under nanoconfinement provide evidence for a two-dimensional (2D) ``square ice'' phase. However, the interpretation of the experiments has been questioned and the stability of square ice has become a matter of debate. Partially this is because the simulation approaches employed so far (force fields and density functional theory) struggle to accurately describe the very small energy differences between the relevant phases. Here we report a study of 2D ice using an accurate wave-function based electronic structure approach, namely diffusion Monte Carlo (DMC). We find that at relatively high pressure, square ice is indeed the lowest enthalpy phase examined, supporting the initial experimental claim. Moreover, at lower pressures, a ``pentagonal ice'' phase (not yet observed experimentally) has the lowest enthalpy, and at ambient pressure, the ``pentagonal ice'' phase is degenerate with a ``hexagonal ice'' phase. Our DMC results also allow us to evaluate the accuracy of various density functional theory exchange-correlation functionals and force field models, and in doing so we extend the understanding of how such methodologies perform to challenging 2D structures presenting dangling hydrogen bonds.