Structure and thermochemistry of Fe2S2−/0/+ gas phase clusters and their fragments. B3LYP calculations

Abstract

The structures and relative energies of different isomers and different electronic states of Fe₂S₂^−/0/+/2+, Fe₂S^−/0/+/2+, Fe₂^−/0/+/2+, FeS₂^−/0/+, FeS^−/0/+, Fe^−/0/+/2+, S₂^−/0, and S^−/0 have been determined by density functional theory (DFT) using the B3LYP functional. Comparison is made with CASSCF/MRCI results for Fe₂, FeS and Fe₂S₂. The broken symmetry approach provides a realistic description of the Heisenberg spin coupling in Fe₂S₂^0/+. The mean absolute deviations of bond dissociation energies, ionization energies and adiabatic electron affinities from available experimental results are 0.18, 0.31 and 0.20 eV, respectively.