Liquid state properties from first principles DFT calculations: Static properties

TL;DR

This paper demonstrates that first-principles DFT calculations can accurately predict liquid properties, supporting the Vibration-Transit theory of liquid dynamics by comparing theoretical results with experimental data for Na and Cu.

Contribution

It shows the feasibility and accuracy of applying DFT to liquid state properties within the V-T theory framework, extending ab initio methods from crystals to liquids.

Findings

Good agreement between DFT calculations and experimental data for volume, bulk modulus, energy, and entropy.

DFT-based liquid property calculations are as reliable as lattice dynamics for crystals.

Supports the validity of V-T theory for liquid dynamics.

Abstract

In order to test the Vibration-Transit (V-T) theory of liquid dynamics, ab initio density functional theory (DFT) calculations of thermodynamic properties of Na and Cu are performed and compared with experimental data. The calculations are done for the crystal at T = 0 and T_m, and for the liquid at T_m. The key theoretical quantities for crystal and liquid are the structural potential and the dynamical matrix, both as function of volume. The theoretical equations are presented, as well as details of the DFT computations. The properties compared with experiment are the equilibrium volume, the isothermal bulk modulus, the internal energy and the entropy. The agreement of theory with experiment is uniformly good. Our primary conclusion is that the application of DFT to V-T theory is feasible, and the resulting liquid calculations achieve the same level of accuracy as does ab initio lattice dynamics for crystals. Moreover, given the well established reliability of DFT, the present results provide a significant confirmation of V-T theory itself.