Structural aspects of an energy-based water classification index and the structure?dynamics link in glassy relaxation

J.M. MONTES DE OCA; APPIGNANESI, G.A.; A. VERDE; L. M. ALARCON; ACCORDINO, SEBASTIÁN R.

THE EUROPEAN PHYSICAL JOURNAL E

Springer

Año: 2021 p. 44 - 47

An energy-based structural indicator for water, V4, has been recently introduced by our group.In turn, in this work we aim at: (1) demonstrating that V4 is indeed able to correctly classify watermolecules between locally structured tetrahedral (T) and locally distorted (D) ones, circumventing theusual problem of certain previous indicators of overestimating the distorted state; (2) correlating V4 withdynamic propensity, a measure of the molecular mobility tendency, in order to seek for the existence ofa connection between structure and dynamics within the supercooled regime. More specifically, in thefirst part of this work we will show that V4 accurately discriminates between merely thermally deformedlocal molecular arrangements and truly distorted molecules (defects). This fact will be made evident notonly from radial distribution function results but also from the dynamic propensity distributions of thedifferent kinds of molecules. In turn, we shall devote the second part of this work to finding correlationsbetween T and D molecules with low- and high-dynamic-propensity molecules, respectively, thus revealingthe existence of a link between local structure and dynamics, while also making evident the dominant roleof the D molecules (defects) in the structural relaxation. Moreover, the availability of a proper molecularclassification technique will enable us to study the timescale of such influence of structure on dynamicsby defining a modified dynamic propensity measure and by applying it to the structured and unstructuredwater molecular states.