Session 4

Structural transitions in liquid water at high temperatures and pressures: A molecular dynamics approach

Ioannis Skarmoutsos
on  Tue, 11:30 for  20min
I. Skarmoutsos, F. Martelli, E. Guardia
1. Laboratory of Physical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
2. Dipartimento di Fisica, Università degli Studi di Roma La Sapienza, Piazzale Aldo Moro 5, Rome 00185, Italy
3. CNR-Istituto dei Sistemi Complessi, Piazzale Aldo Moro 5, Rome 00185, Italy
4. Departament de Física, Universitat Politècnica de Catalunya, Campus Nord-Edifici B4-B5, Jordi Girona 1-3, Barcelona E-08034, Spain
iskarmoutsos@uoi.gr

Abstract

Molecular dynamics simulations of liquid water were performed using the TIP4P-2005 model at elevated pressures, spanning temperatures from ambient to near-critical conditions. Analysis of local structural, dynamical, and entropic properties reveals two distinct structural transitions occurring in intermediate and high-temperature regimes. These are marked by extrema and crossovers in multiple descriptors, along with significant rearrangements of the hydrogen-bond network. The structural changes are further reflected in intermolecular vibrational and librational dynamics, as evidenced by modifications in velocity correlation spectral densities and in translational and rotational densities of states.

References

[1] I. Skarmoutsos, F. Martelli, and E. Guardia, J. Chem. Phys., 164, 054503 (2026).

[2] I. Skarmoutsos, and E. Guardia, Chem. - Eur. J., 31, e202500423 (2025).