Structure and thermochemistry of Fe2S2−/0/+ gas phase clusters and their fragments. B3LYP calculations
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 Fe2S20/+. 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.