Structural, Electronic and Magnetic Properties of S 0/±8 and S8X0/± Clusters, X = (Sc-Ni)

Abstract

The geometric, electronic and magnetic properties of neutral and charged S\(_{8}^{0/\pm }\) and S\(_{8}\)X\(^{0/\pm }\), X = (Sc-Ni), clusters have been investigated in the framework of the density functional theory, within the generalized gradient approximation for the exchange and correlation. Results indicate that the most stable structure of S\(_{8}\) cluster is the D\(_{4d}\) crown shaped geometry. The calculated values of the bond length, S-S-S angle, vibrational frequency and adiabatic ionization potential of S\(_{8}\) cluster are found to be in good agreement with the available experimental data. Doping with a single X impurity is enough to change the structure of the sulfur cluster to a large extent. The X atom is always adsorbed in the center of the sulfur host. For all doped clusters, only three-dimensional low-energy isomers are found. The impact of transition-metal doping of sulfur clusters on the atomic structure, stability, and reactivity is determined through the analysis of the binding energy per atom and global reactivity indicators like the electronegativity and chemical hardness. All doped clusters show larger binding energies with respect to the pure one, indicating that doping could stabilize the S\(_8\) cluster, and enhances the thermodynamic stability of the host. According to the HOMO-LUMO gaps, the doped cluster S\(_8\)Fe could have interesting optical properties. Doping change the magnetic state and the magnetic moment distribution in the S\(_{8}\) host. A completely quenched dopant magnetic moment is found in S\(_{8}\)Sc\(^{-}\), S\(_{8}\)Ti, S\(_{8}\)V\(^{\pm }\), and S\(_{8}\)Co\(^{\pm }\), while high spin magnetic moments are located on S\(_{8}\)Cr\(^{0/-}\), S\(_{8}\)Mn\(^{0/\pm }\), and S\(_{8}\)Fe\(^{0/-}\) clusters. In order to explain the changes of the magnetic moments within doped clusters, partial densities of states are discussed in detail.