Dynamical Heterogeneity in Supercooled Water and its Spectroscopic Fingerprints

Fuente: arXiv
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Hauptverfasser: Malosso, Cesare, Donkor, Edward Danquah, Baroni, Stefano, Hassanali, Ali
Format: Preprint
Veröffentlicht: 2025
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author Malosso, Cesare
Donkor, Edward Danquah
Baroni, Stefano
Hassanali, Ali
author_facet Malosso, Cesare
Donkor, Edward Danquah
Baroni, Stefano
Hassanali, Ali
contents A growing body of theoretical and experimental evidence strongly supports the existence of a second liquid-liquid critical point (LLCP) in deeply supercooled water leading to the co-existence of two phases: a high-and low-density liquid (HDL and LDL). While the thermodynamics associated with this putative LLCP has been well characterised through numerical simulations, the dynamical properties of these two phases close to the critical point remain much less understood. In this work, we investigate their dynamical and spectroscopic features using machine-learning interatomic potentials (MLIPs). Dynamical analyses using the van-Hove correlation function, reveal that LDL exhibits very sluggish and heterogeneous molecular mobility, in contrast to the faster and more homogeneous dynamics of HDL. Infrared absorption (IR) spectra further show clear vibrational distinctions between LDL and HDL, in particular in the far IR region between 400 - 1000 cm-1. Together, these findings provide new dynamical fingerprints that clarify the microscopic behavior of supercooled water and offer valuable guidance for experimental efforts aimed at detecting the long-sought liquid-liquid transition.
format Preprint
id arxiv_https___arxiv_org_abs_2506_24055
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dynamical Heterogeneity in Supercooled Water and its Spectroscopic Fingerprints
Malosso, Cesare
Donkor, Edward Danquah
Baroni, Stefano
Hassanali, Ali
Soft Condensed Matter
A growing body of theoretical and experimental evidence strongly supports the existence of a second liquid-liquid critical point (LLCP) in deeply supercooled water leading to the co-existence of two phases: a high-and low-density liquid (HDL and LDL). While the thermodynamics associated with this putative LLCP has been well characterised through numerical simulations, the dynamical properties of these two phases close to the critical point remain much less understood. In this work, we investigate their dynamical and spectroscopic features using machine-learning interatomic potentials (MLIPs). Dynamical analyses using the van-Hove correlation function, reveal that LDL exhibits very sluggish and heterogeneous molecular mobility, in contrast to the faster and more homogeneous dynamics of HDL. Infrared absorption (IR) spectra further show clear vibrational distinctions between LDL and HDL, in particular in the far IR region between 400 - 1000 cm-1. Together, these findings provide new dynamical fingerprints that clarify the microscopic behavior of supercooled water and offer valuable guidance for experimental efforts aimed at detecting the long-sought liquid-liquid transition.
title Dynamical Heterogeneity in Supercooled Water and its Spectroscopic Fingerprints
topic Soft Condensed Matter
url https://arxiv.org/abs/2506.24055