Working and educating for life: Feminist and international perspectives on adult education

Abstract

From density functional DFT investigations, pairs of Fe (diiron), mostly known in molecular diiron nona-carbonyl Fe2(CO)9 and diiron-mono-carbide Fe2C, are embedded in hexagonal C6 substructures. Based on formerly studied parent structure (FeC6), Fe2C6 and Fe2C12 modeling Fe-network-embedded graphene are shown to be more cohesive than the mono-carbide on one hand, and increasingly cohesive from hexa- C6 to dodeca- C12 on the other hand. From energy differences, the ground state is spin-polarized SP, versus a non-spin-polarized NSP configuration, and identified as ferromagnetic versus a higher energy anti-ferromagnetic hypothesis. The projection of the magnetic charge density on Fe and C shows that only Fe carries the magnetic moment; while carbon receives charges from Fe as illustrated by the electron localization function ELF 3D and 2D mapping. SP configuration induces an enlarged c/a hexagonal ratio, versus NSP, while ahex. remains constant thanks to the rigid C6 carbon substructure network, resulting in an anisotropic magneto-volume response. This feature essentially due to in-plane diiron is discussed from the energy-volume (E, V) NSP and SP equations of state EOS and derived quantities like volume and d(Fe-Fe) change of the magnetization. Such model structures find support from experimental evidence of multiatomic Fe networks embedded in graphene.