We present quantum molecular dynamics calculations of thermophysical properties of solid and liquid zirconium in the vicinity of melting. An overview of available experimental data is also presented. We focus on the analysis of thermal expansion, molar enthalpy, resistivity, and normal spectral emissivity of solid and liquid Zr. Possible reasons of discrepancies between the first-principles simulations and experiments are discussed. Our calculations reveal a significant volume change on melting in agreement with electrostatic levitation experiments. Meanwhile, we confirm a low value of enthalpy of fusion obtained in some pulse-heating experiments. Electrical resistivity of solid and liquid Zr is systematically underestimated in our simulations, however, the slope of resistivity temperature dependencies agrees with experiments. Our calculations predict almost constant normal spectral emissivity in liquid Zr.

In this work we present the melting curves of hafnium and zirconium obtained using quantum molecular dynamics calculations. The mean-square displacements computed during ab initio simulations of a crystal phase are used to reconstruct the melting curve according to the Lindemann criterion. The resulting Zr melting curve shows a steeper slope in the low-pressure region compared to some recent diamond-anvil cell experiments but agrees with our previous estimate via the Clausius-Clapeyron relation. The slope for higher pressures is consistent with the experimental one. As for Zr, the Hf melting curve also has a similar steep initial slope being in agreement with our estimate from the Clausius-Clapeyron relation. Currently there are no data on the melting of Hf above atmospheric pressure, so we demonstrate the first ab initio estimate of the melting curve of Hf up to 225 GPa.

Our study is devoted to the thermophysical properties of solid and liquid nickel in the vicinity of the melting point. For this purpose, we use a first-principles calculation method based on quantum molecular dynamics and experimental measurements with a pulse heating technique. We provide experimental and calculated data on thermal expansion, molar enthalpy, sound velocity, resistivity, and normal spectral emissivity and analyze them together with available experimental and reference data on solid and liquid Ni. We confirm experimentally and computationally the strong temperature dependence of Ni density observed in several experiments. Our fusion enthalpy measurements are in good agreement with the recommended literature data, and the calculation predicts a slightly smaller change in enthalpy. The experimental measurements of nickel resistivity in the solid and liquid states agree with previous experimental data that take into account its correction for thermal expansion. At the same time, our calculation of the resistivity in the solid phase shows a systematic shift. For liquid nickel, we report a weak nonlinear temperature dependence of the normal spectral emissivity. Thus, taking advantage of experimental and ab initio computational approaches, we present consistent data on the thermophysical properties of solid and liquid Ni.

The dynamic electrical conductivity of dense Zr plasma near melting is calculated using ab initio molecular dynamics and the Kubo–Greenwood formula. The antisymmetrization of the electronic wave function is considered with the determinant of one-electron wave functions; exchange and correlation effects are treated via an exchange–correlation functional. Optical properties are restored using the Kramers–Kronig transformation. The influence of computational parameters and inner shell electrons on the results is thoroughly investigated. We demonstrate the convergence of our computations and analyze comparison with experimental data.

Substances with a complex electronic structure exhibit non-Drude optical properties that are challenging to interpret experimentally and theoretically. In our recent paper [ Phys. Rev. E 105, 035307 (2022)], we offered a computational method based on the continuous Kubo-Greenwood formula, which expresses dynamic conductivity as an integral over the electron spectrum. In this Letter, we propose a methodology to analyze the complex conductivity using liquid Zr as an example to explain its nontrivial behavior. To achieve this, we apply the continuous Kubo-Greenwood formula and extend it to include the imaginary part of the complex conductivity into the analysis. Our method is suitable for a wide range of substances, providing an opportunity to explain optical properties from ab initio calculations of any difficulty.