Electrocatalytic Oxidation Of Methanol By The [ru3o(oac) 6(py)2(ch3oh)]3+ Cluster: Improving The Metal-ligand Electron Transfer By Accessing The Higher Oxidation States Of A Multicentered System

The [Ru3O(Ac)6(py)2(CH3OH)] + cluster provides an effective electrocatalytic species for the oxidation of methanol under mild conditions. This complex exhibits characteristic electrochemical waves at -1.02, 0.15 and 1.18 V, associated with the Ru3 III,II,II/Ru3 III,III,II/ Ru3 III,III,III/Ru3 IV,III,III successive redox couples, respectively. Above 1.7 V, formation of two Ru IV centers enhances the 2-electron oxidation of the methanol ligand yielding formaldehyde, in agreement with the theoretical evolution of the HOMO levels as a function of the oxidation states. This work illustrates an important strategy to improve the efficiency of the oxidation catalysis, by using a multicentered redox catalyst and accessing its multiple higher oxidation states.331020462050Viertler, H., Gruber, J., Pardini, V.L., (2001) Organic Electrochemistry, p. 621. , Lund, H.Hammerich, O., eds.Marcel Dekker: New York, chap. 17Araki, K., Toma, H.E., (2006) N-4 Macrocyclic Metal Complexes, p. 255. , Zagal, J. H.Bedioui, F.Dodelet, J.-P.Springer: New York, chap. 6Araki, K., Dovidauskas, S., Winnischofer, H., Alexiou, A.D.P., Toma, H.E., (2001) J. Electroanal. Chem., 498, p. 152Dovidauskas, S., Toma, H.E., Araki, K., Sacco, H.C., Iamamoto, Y., (2000) Inorg. Chim. Acta, 305, p. 208Toma, H.E., Araki, K., (2009) Progr. Inorg. Chem., 56, p. 379Kuwabara, I.H., Comninos, F.C.M., Pardini, V.L., Viertler, H., Toma, H.E., (1994) Electrochim. Acta, 39, p. 2401Nunes, G.S., Alexiou, A.D.P., Araki, K., Formiga, A.L.B., Rocha, R.C., Toma, H.E., (2006) Eur. J. Inorg. Chem., p. 1487Nunes, G.S., Alexiou, A.D.P., Toma, H.E., (2008) J. Catal., 260, p. 188Alexiou, A.D.P., Dovidauskas, S., Toma, H.E., (2000) Quim. Nova, 23, p. 785Toma, H.E., Araki, K., Alexiou, A.D.P., Nikolaou, S., Dovidauskas, S., (2001) Coord. Chem. Rev., 219-221, p. 187Davis, S., Drago, R.S., (1988) Inorg. Chem., 27, p. 4759Bilgrien, C., Davis, S., Drago, R.S., (1987) J. Am. Chem. Soc., 109, p. 3786Sieben, J.M., Duarte, M.M.E., Mayer, C.E., (2010) Chem Cat. Chem, 2, p. 182Raoof, J.B., Golikan, A.N., Baghayeri, M., (2010) J. Solid State Electrochem., 14, p. 817Raoof, J.B., Karimi, M.A., Hosseini, S.R., Mangelizadeh, S., (2010) J. Electroanal. Chem., 638, p. 33El-Deab, M.S., (2009) Int. J. Electrochem. Sci., 4, p. 1329Zheng, L., Song, J.F., (2010) J. Solid State Electrochem., 14, p. 43Wu, B.H., Hu, D., Kuang, Y.J., Liu, B., Zhang, X.H., Chen, J.H., (2009) Angew. Chem., Int. Ed., 48, p. 4751Suffredini, H.B., Salazar-Banda, G.R., Avaca, L.A., (2009) J. Sol-Gel Sci. Technol., 49, p. 131Balasubramanian, A., Karthikeyan, N., Giridhar, V.V., (2008) J. Power Sources, 185, p. 670Zhao, H.B., Li, L., Yang, J., Zhang, Y.M., (2008) Electrochem. Commun., 10, p. 1527Zhang, D., Ding, Y., Gao, W., Chen, H.Y., Xia, X.H., (2008) J. Nanosci. Nanotechnol., 8, p. 979Sawyer, D.T., Roberts, J.L., (1974) Experimental Electrochemistry for Chemists, , Wiley: New YorkBaumann, J.A., Salmon, D.J., Wilson, S.T., Meyer, T.J., Hatfield, W.E., (1978) Inorg. Chem., 17, p. 3342Allinger, N.L., (1977) J. Am. Chem. Soc., 99, p. 8127Zerner, M.C., Loew, G.H., Kirchner, R.F., Mueller-Westerhoff, U.T., (1980) J. Am. Chem. Soc., 102, p. 589Formiga, A.L.B., Nogueira, A.F., Araki, K., Toma, H.E., (2008) New J. Chem., 32, p. 1167Longuet-Higgins, H., Pople, J.A., (1955) Proc. Phys. Soc., 68, p. 591Latimer, W.M., (1952) The Oxidation States of the Elements and Their Potentials in Aqueous Solutions, , Prentice-Hall: Englewood Cliffs, 2nd edNicholson, R.S., Shain, I., (1964) Anal. Chem., 36, p. 706Sundholm, G., (1971) Acta Chem. Scand., 25, p. 3188Sundholm, G., (1971) J. Electroanal. Chem., 31, p. 265Nash, T., (1953) Biochemistry, 55, p. 41

Elementary excitations of trapped Bose gas in the large-gas-parameter regime

We study the effect of going beyond the Gross-Pitaevskii theory on the frequencies of collective oscillations of a trapped Bose gas in the large gas parameter regime. We go beyond the Gross-Pitaevskii regime by including a higher-order term in the interatomic correlation energy. To calculate the frequencies we employ the sum-rule approach of many-body response theory coupled with a variational method for the determination of ground-state properties. We show that going beyond the Gross-Pitaevskii approximation introduces significant corrections to the collective frequencies of the compressional mode.Comment: 17 pages with 4 figures. To be published in Phys. Rev.

Energy dependent scattering and the Gross-Pitaevskii Equation in two dimensional Bose-Einstein condensates

We consider many-body effects on particle scattering in one, two and three dimensional Bose gases. We show that at zero temperature these effects can be modelled by the simpler two-body T-matrix evaluated off the energy shell. This is important in 1D and 2D because the two-body T-matrix vanishes at zero energy and so mean-field effects on particle energies must be taken into account to obtain a self-consistent treatment of low energy collisions. Using the off-shell two-body T-matrix we obtain the energy and density dependence of the effective interaction in 1D and 2D and the appropriate Gross-Pitaevskii equations for these dimensions. We present numerical solutions of the Gross-Pitaevskii equation for a 2D condensate of hard-sphere bosons in a trap. We find that the interaction strength is much greater in 2D than for a 3D gas with the same hard-sphere radius. The Thomas-Fermi regime is therefore approached at lower condensate populations and the energy required to create vortices is lowered compared to the 3D case.Comment: 22 pages, 6 figure

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters

Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review