Reparameterization of hybrid functionals based on energy differences of states of different multiplicity

Probing the structures of gas-phase rhodium cluster cations by far-infrared spectroscopy

“…5 PBE1 favored slightly higher multiplicities than PBE, presumably due to Hartree-Fock's favoring of openshell systems. 56 As we have previously reported, 32 the choice of the PBE or PBE1 functionals changed the favored geometry of the Rh + 8 cluster from cubic to a close-packed bicapped octahedron (bc-oh), presumably due to the inclusion of a portion of partial exact exchange in PBE1. We have found similar effects for most cluster sizes in the range (n = 6-12) that we discuss here, where it was seen that geometries with square or cubic motifs were favored by PBE whilst close-packed geometries were favored by PBE1.…”

Iron-catalysed transformation of molecular dinitrogen into silylamine under ambient conditions

“…DFT calculations were performed to search all intermediates and transition structures on potential energy surfaces by using the Gaussian 09 program 29 . Because the relative energy of different spin states was found to be of great importance in the present monoiron system, we adopted the B3LYP* functional, [30][31][32] which is a reparametrised version of the B3LYP hybrid functional 33,34 developed by Reiher et al 30,31 The B3LYP functional is known to be reliable when applied for molecular and enzymatic systems containing transition metals, but it tends to overestimate the spin-state splitting [35][36][37][38] . Advantages of the B3LYP* functional in the evaluation of the spin-state splitting have been reported for several iron complexes exhibiting spin-crossover phenomena [30][31][32]39 .…”

Computational insights into the O2-evolving complex of photosystem II

“…This work has been essential for validating the DFT level of theory, as applied to Mn complexes, since hybrid density functionals were known to exhibit shortcomings in the description of lowlying spin states of open-shell transition-metal complexes Ghosh & Steene 2001;Ghosh & Taylor 2005;Koch & Holthausen 2001;Lundberg & Siegbahn 2005b;Reiher et al 2001a;Reiher et al 2001b (Sproviero et al 2006a). These complexes involve unpaired spins with frustrated antiferromagnetic couplings that required to be addressed in terms of the broken symmetry (BS) DFT method (Noodleman 1981;Noodleman & Case 1992;Noodleman & Davidson 1986;Noodleman et al 1995).…”

“…These errors were comparable to typical structural rearrangements in the OEC metal cluster, induced by oxidation of the constituent ions (i.e., changes of Mn ligand bond-lengths in the 0.1-0.2 Å), and therefore required further analysis. In addition, hybrid functionals were known to overestimate the relative stability of high-spin over low-spin states of transition metal complexes (Koch & Holthausen 2001;Reiher et al 2001a), a difficulty that could be critical in the process of identifying the nature of ground electronic states, or in studies of spincrossover phenomena in transition metal complexes (Harvey 2001;Harvey et al 2003;Holthausen 2005;Reiher et al 2001a;Schroder et al 2000;Shaik et al 2002).…”