Transverse excitations in liquid Sn.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Physics

Background:

• Understanding dynamic properties of liquid metals is crucial for materials science.
• Transverse acoustic (TA) modes, common in solids, are less understood in liquid states.
• Inelastic X-ray scattering (IXS) is a powerful tool for probing atomic dynamics.

Purpose of the Study:

• To experimentally observe and characterize transverse acoustic (TA) excitation modes in liquid tin (Sn).
• To validate experimental findings with theoretical predictions from ab initio molecular dynamics simulations.
• To establish a method for detecting TA modes in liquid systems through specific spectral features.

Main Methods:

• Inelastic X-ray Scattering (IXS) experiments were performed on liquid tin.
• Ab initio molecular dynamics (AIMD) simulations were conducted for theoretical comparison.
• Analysis focused on comparing experimental IXS spectra with simulated longitudinal current correlation spectra.

Main Results:

• Transverse acoustic (TA) excitation modes were successfully observed in the IXS spectra of liquid Sn.
• Experimental excitation energies and widths of TA modes showed good agreement with AIMD simulation results.
• Quantitative comparison revealed that TA modes are detectable via quasi-TA branches in longitudinal current correlation spectra.

Conclusions:

• The study confirms the existence and experimental detectability of TA modes in liquid tin.
• The findings validate the accuracy of ab initio molecular dynamics simulations for describing liquid metal dynamics.
• Determined TA mode lifetime (~0.7 ps) and propagation length (~0.8-1.0 nm) correlate with the dynamic cage structure in liquid Sn.