Atomic interactions at the interface between iron or iron fluoride, and sodium by the first-principles calculation

浪江 将成 ; 斉藤 淳一  

Namie, Masanari; Saito, Junichi

Atomic interactions at the interface involving iron, iron fluorides (iron (II) fluoride and iron (III) fluoride), and sodium were investigated using first-principles calculations. The wettability with liquid sodium was subsequently examined, focusing on the calculated atomic interactions. From a covalent bonding perspective, iron (II) fluoride exhibited weaker bonds between neighboring atoms in the substrate material than iron (III) fluoride. However, it exhibited relatively strong bonds between the substrate material and sodium atoms. In contrast, iron (III) fluoride had stronger bonds between neighboring atoms in the substrate material, with weaker bonds between the substrate material and sodium atoms. Additionally, in terms of ionic bonding, the contact of the sodium atom with the substrate material increased the charge transfer of the substrate material atom, correlating with the oxidation number of iron. Iron (III) fluoride exhibited the most substantial charge transfer among the substrate materials. The charge transfer from the sodium atom to the atom in contact with it was approximately 2.5 times that of iron. This result underscores the change in electronic states induced by the iron or iron fluoride interface, potentially influencing the wettability between the material surface and liquid sodium.