Experimental determination of the temperature-dependent Van Hove function in a Zr80Pt20 liquid

Abstract

Even though the viscosity is one of the most fundamental properties of liquids, the connection with the atomic structure of the liquid has proven elusive. By combining inelastic neutron scattering with the electrostatic levitation technique the time-dependent pair-distribution function (i.e. the Van Hove function) has been determined for liquid Zr 80 Pt 20 . We show that the decay-time of the first peak of the Van Hove function is directly related to the Maxwell relaxation time of the liquid, which is proportional to the shear viscosity. This result demonstrates that the local dynamics for increasing or decreasing the coordination number of local clusters by one determines the viscosity at high temperature, supporting earlier predictions from molecular dynamics simulations.

Resistivity Saturation in Metallic Liquids Above a Dynamical Crossover Temperature Observed in Measurements Aboard the International Space Station

“…Although liquids cannot sustain long wavelength phonons, short wavelength (high frequency) phonons are excited in short-lived solidlike regions, as suggested by Frenkel [53], and has been observed in inelastic scattering experiments [54]. With increasing temperature, the length scales and timescales of the dynamically evolving solidlike regions (atomic clusters) in a liquid decrease [12][13][14]46,52]. Above some temperature, the mean electron scattering time and the structural relaxation time may become comparable.…”

“…Since the dynamical crossover is observed in all liquids [11,18,55], except for the very strong ones, resistivity saturation may be a universal property of liquids. That the saturation coincides with T A is perhaps the most direct evidence that the structure of the liquid at the atomic level strongly couples to the dynamics at a longer, hydrodynamic, level [52].…”

“…It is well known that the spatial and temporal changes of the liquid structure (structural relaxations) are strongly temperature dependent. The timescales for structural relaxation change from about 100 s near T g to 10 −12 -10 −14 s in the equilibrium liquids [12][13][14]52]. Since the typical scattering time for electrons is in the nano-to femtoseconds range, the liquid structure appears as static to the electrons in most of the supercooled states.…”

Magnetic excitations, non-classicality and quantum wake spin dynamics in the Hubbard chain

“…fluids, where G(r, t) may be understood as the average number density at r and t given that a particle was at the origin at time t = 0. This picture has been used to interpret experimental data on liquid lead [25], water [26] and Zr 80 Pt 20 [27,28].…”

Real-Space Local Dynamics of Molten Inorganic Salts Using Van Hove Correlation Function

“…14,16 Recent progress in time-of-flight inelastic neutron scattering 22 as well as high-resolution inelastic X-ray scattering 23,24 reduces the termination errors significantly and enables us to convert the spectra in reciprocal space into the real-space correlation functions, as demonstrated for water and metallic liquid systems. 14,16,17 To understand the short-time local dynamics of ions in molten salts, we carried out inelastic neutron scattering (INS) measurements of molten MgCl 2 salt at ARCS 25 at the SNS 26 (see Methods for details). We first merged the INS spectra taken with different incident neutron energies (20, 40, and 80 meV) such that the spectra with the lower energy are used as much as possible.…”