Toward Understanding the Electron Density Distribution in Magnetic Clusters: Insight from the ELF and AIM Analyses of Ground-State Fe4

Abstract

Topological analysis of the electron localization function (ELF) in the ground-state Fe4 cluster reveals different regions of valence electron localization in terms of monosynaptic V(Fei), disynaptic V(Fei,Fej), trisynaptic V(Fei,Fej,Fek), and tetrasynaptic V(Fe1,Fe2,Fe3,Fe4) bonding valence attractors and basins. The degree of electron localization is found to be smaller than in a homogeneous electron gas with η(r) ≤ 0.490. A relative fluctuation of the electron density in the valence basins ranges between 0.83 and 0.96, which indicates a rather substantial delocalization of the electron density. Approximately three valence α-electrons are localized at each iron core C(Fei=1,4) while two α-electrons, i.e., 0.5 e per one atom, are delocalized over the cluster. The valence electrons show a trend toward localization between iron sites and in the proximity of triangular faces of the cluster with the basin population of one electron. Metallic bonds in Fe4 may be characterized as partially covalent and highly ...