title: Spin multiplicity and symmetry breaking in vanadium-benzene complexes.
abstract: We present accurate quantum Monte Carlo (QMC) calculations which enabled us to determine the structure, spin multiplicity, ionization energy, dissociation energy, and spin-dependent electronic gaps of the vanadium-benzene system. From total and ionization energy we deduce a high-spin state with vastly different energy gaps for the two spin channels. For this purpose we have used a multistage combination of techniques with consecutive elimination of systematic biases except for the fixed-node approximation in QMC calculations. Our results significantly differ from the established picture based on previous less accurate calculations and point out the importance of high-level many-body methods for predictive calculations of similar transition metal-based organometallic systems.
authors.affiliation: Institute of Physics, CCMS, Slovak Academy of Sciences, Bratislava, Slovakia.
authors.forename: L
authors.initials: L
authors.lastname: Horváthová
authors.forename: M
authors.initials: M
authors.lastname: Dubecký
authors.forename: L
authors.initials: L
authors.lastname: Mitas
authors.forename: I
authors.initials: I
authors.lastname: Stich