Evidence of ferroelectric features in low-density supercooled water from ab initio deep neural-network simulations

• 成果类型: Article
• 署名作者: Malosso, Cesare; Manko, Natalia; Izzo, Maria Grazia; Baroni, Stefano; Hassanali, Ali
• 署名单位: International School for Advanced Studies (SISSA); Abdus Salam International Centre for Theoretical Physics (ICTP)
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11135
• DOI: 10.1073/pnas.2407295121
• 发表日期: 2024-08-06
• 关键词: liquid-liquid transition; potential-energy surface; MODEL; DYNAMICS; spectrum; point

摘要

Over the last decade, an increasing body of evidence has emerged, supporting the existence of a metastable liquid-liquid critical point in supercooled water whereby two distinct liquid phases of different densities coexist. Analyzing long molecular dynamics simulations performed using deep neural-network force fields trained to accurate quantum mechanical data, we demonstrate that the low-density liquid phase displays a strong propensity toward spontaneous polarization, as witnessed by large and long-lived collective dipole fluctuations. Our findings suggest that the dynamical stability of the low-density phase, and hence the transition from high-density to low-density liquid, is triggered by a collective process involving an accumulation of rotational angular jumps, which could ignite large dipole fluctuations. This dynamical transition involves subtle changes in the electronic polarizability of water molecules which affects their rotational mobility within the two phases. These findings hold the potential for catalyzing activity in the search for dielectric-based probes of the putative second critical point.