Spin state relaxation of iron complexes: The case for OPBE and S12g

Abstract

The structures of nine iron complexes that show a diversity of experimentally observed spin ground states are optimized and analyzed with Density Functional Theory (DFT). An extensive validation study of the new S12g functional is performed, with the discussion concerning the influence of the environment, geometry and its overall performance based on the comparison with the well proven OPBE functional. The OPBE and S12g functionals give the correct spin ground state for all investigated iron complexes. Since S12g performs remarkably well it can be considered a reliable tool for studying spin state energetics in complicated transition metal systems