Computational insights into the structural, thermodynamic and transport properties of CaF2-MgF2 binary fluoride system at high temperatures

Layout of structural, thermodynamic and transport properties of CaF2-MgF2 binary fluoride system. [Display omitted] •Neural network interatomic potentials of CaF2-MgF2 molten salt are trained and established by AIMD.•Density, thermodynamic and transport properties are estimated and compared between AIMD, NNIPs-IPMD and Matlantis with PFP.•EOS procedure with DFT-D3 dispersion in AIMD gives the best predictions of equilibrium volumes.•Cation-centered adjacent polyhedrons are more likely connected with edge-sharing or face-sharing rather than corner-sharing fluorine.•Matlantis could be considered as an alternative and high efficiency MD simulation tool especially for the higher-order large system. The structural, thermodynamic and transport properties of the CaF2-MgF2 molten salt system were investigated with ab initio molecular dynamics (AIMD), system-specific neural network interatomic potentials (NNIPs) and universal PreFerred Potentials (PFP). We trained an NNIP model using AIMD data as input and used this potential to efficiently simulate the interactions within a large supercell in a temperature range of 1273–1773 K. The Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) code was employed to validate our trained NNIP model. The Matlantis software with universal PFP is also presented to prove its feasibility for MD calculations and can be considered as a useful alternative simulation tool for higher-order systems where existing potentials are not readily available. We calculated structural and thermodynamic properties including radial distribution function (RDF), angular distribution function (ADF), specific heat capacity, ionic self-diffusivity, and viscosity. Our results indicate that the system exhibited a high degree of structural disorder, with the Ca, Mg, and F ions forming a liquid solution. Using PFP, the positions of the first peak in RDFs for Ca-F and Mg-F pairs are only slightly left-shifted (