Scaling in second order electron correlation calculations of potential energy curves and spectroscopic constants

The determination of potential energy curves and spectroscopic constants using the method of scaling in second order electron correlation calculations is investigated. An application to the ground state of the fluorine molecule is described using full fourth order many-body perturbation theory within two basis sets.     

Kondo lattice state within the slave boson approach: spin-split masses and effective interaction among heavy quasiparticles

We provide a brief overview of our Hamiltonian approach to the the Kondo-lattice state at both finite Coulomb interaction U and nonzero applied magnetic field. In the mean-field approximation we introduce the spindependent effective masses, as well as calculate the effective Kondo (hybridization) temperature as a function of U. The effective interaction coming from the slave-boson exchange is shown to contain both the local (intraband) pairing and the Kondo (interband) interaction.     

Enhanced activity and selectivity in cyclohexane autoxidation by inert H-bond acceptor catalysts.

Herein, we demonstrate that the chain-initiating dissociation of cyclohexyl hydroperoxide, CyOOH, is substantially accelerated by H-bond acceptors (e.g. Teflon), which assist O-O bond breaking by stabilising the leaving *OH radical. This is a completely new approach to boost the chain-propagating radical concentration. Indeed, up to now, literature has remained focussed on transition metal catalysis. In addition to this initiation effect, we demonstrate how inert perfluorinated compounds are also able to steer the selectivity at the molecular level, by promoting the conversion of the intermediate cyclohexyl hydroperoxide to the most desired end-product, cyclohexanone. This effect is explained by an enhanced, H-bond-assisted, hydroperoxide propagation. This hitherto overlooked hydroperoxide propagation was recently presented by us as the dominant cyclohexanone and cyclohexanol source. We herein thus confirm our previously reported autoxidation scheme, and illustrate its usefulness as a solid basis for designing new catalytic systems.     

Edge-Ends in Countable Graphs

We introduce the notion of an edge-end and characterize those countable graphs which have edge-end-faithful spanning trees. We also prove that for a natural class of graphs, there always exists a tree which is faithful on the undominated ends and rayless over the dominated does.     

Electrostatic Potential Field and Nucleophilicity of 3, 5, 8, 10-Tetramethyl-aceheptylene

The electrostatic potential (EP.) for aceheptylene (I) is calculated using ab-initio wavefunctions. In addition, the EP. around I is approximated by a monopole expression, using wavefunctions from various semiempirical procedures as a basis. It is found that the previously noted discrepancy between the thoretical prediction of differential nuclophilicity of the individual unsaturated C-atoms in 3,5,8,10-tetramethyl-aceheptylene(II) and the experimental results of protonation is removed, if instead of local atomic charges, the EP. around II, approximated by that of I is considered.     

Internal motion in 1-methylnaphthalene. A variable temperature NMR study using C and H spin—lattice relaxation time measurements

¹³C nuclear spin—lattice relaxation times of 1-methylnaphthalene and ²H nuclear spin—lattice relaxation times of the perdeuterated species, both in deuterochloroform solutions, were measured at several different temperatures. The effects of isotopic substitution on the effective correlation times are discussed. The Woessner approach to extracting the internal jump rates of the CH₃ and CD₃ groups from these relaxation times was used. Activation energies for the internal motions were calculated by fitting the temperature dependent jump rates to an Arrhenius type expression. The differences between the activation energies of the two isotopic species are discussed.