43,064 research outputs found
Normal and off-normal incidence dissociative dynamics of O 2 ( v , J ) on ultrathin Cu films grown on Ru(0001)
No full textThe dissociative adsorption of molecular oxygen on metal surfaces has long been controversial, mostly due to the spin-triplet nature of its ground state, to possible non-adiabatic effects, such as an abrupt charge transfer from the metal to the molecule, or even to the role played by the surface electronic state. Here, we have studied the dissociative adsorption of O2on CuML/Ru(0001) at normal and off-normal incidence, from thermal to super-thermal energies, using quasi-classical dynamics, in the framework of the generalized Langevin oscillator model, and density functional theory based on a multidimensional potential energy surface. Our simulations reveal a rather intriguing behavior of dissociative adsorption probabilities, which exhibit normal energy scaling at incidence energies below the reaction barriers and total energy scaling above, irrespective of the reaction channel, either direct dissociation, trapping dissociation, or molecular adsorption. We directly compare our results with existing scanning tunneling spectroscopy and microscopy measurements. From this comparison, we infer that the observed experimental behavior at thermal energies may be due to ligand and strain effects, as already found for super-thermal incidence energies.Fil: Fallaque, J. G.. Universidad Autónoma de Madrid; España. Instituto Madrileño de Estudios Avanzados en Nanociencia; EspañaFil: Ramos Acevedo, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Busnengo, Heriberto Fabio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: Martín, F.. Universidad Autónoma de Madrid; España. Instituto Madrileño de Estudios Avanzados en Nanociencia; EspañaFil: Díaz, C.. Universidad Complutense de Madrid; Españ
[Letter to J. G. O'Rielly Regarding Firefighting - October 15, 1943]
No full textLetter to J. G. O'Rielly of W. S. Darley & Company discussing the champion type "H" pump and an enclosed list of fire chiefs located throughout the Middle East. The author of this letter recommends that Mr. Rielly send photographs and the highest pressure recorded on this pump to Captain James C. Thompson
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays
No full textFirst observations of the B0s
→ψ(2S)η, B0 →ψ(2S)π
+
π
− and B0s
→ψ(2S)π
+
π
− decays are made
using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in
proton–proton collisions at a centre-of-mass energy of
√
s = 7 TeV. The ratios of the branching fractions
of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are
B(B0s
→ψ(2S)η)
÷
B(B0s
→J/ψη)
= 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B),
;
B(B0→ψ(2S)π
+
π
−
)
÷
B(B0→J/ψπ
+
π
−
)
= 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B),
;
B(B0s
→ψ(2S)π
+
π
−
)
÷
B(B0s
→J/ψπ
+
π
−
)
= 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B),
where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ
and ψ(2S) meson decays
Tailoring single-molecule conductance with structured graphene electrodes
No full textModulation of electric currents through single-molecule junctions is usually achieved by synthesis of molecules with desired functionalities, in conjunction with suitable molecule–electrode contacts through specific anchoring groups. An alternative to this approach, barely explored so far, is to use structured electrodes, where conductivity could eventually be controlled by changing the specific anchoring site within the very same electrode. Here, we theoretically investigate how to exploit the pronounced anisotropy of corrugated graphene deposited on Ru(0001) (Gr/Ru) to tailor single-molecule conductivity in 4-aminophenyl and 4-aminobenzonitrile. We show that currents induced in the upper and lower anchoring positions in the Gr/Ru moiré are substantially different, irrespective of the chosen molecule. The magnitude of these currents can differ by as much as an order of magnitude at specific bias voltages. We also show that both molecules display rectifying properties, which can differ by up to a factor of five in different anchoring sites. Interestingly, the observed modulations strongly depend on the chemical binding nature between the molecule and the electrode, (strong) covalent bond for 4-aminophenyl and (weak) physisorption for 4-aminobenzonitrile. All this suggests that Gr/Ru can be an ideal electrode to modulate single-molecule electric conductivity under experimental conditions that are available in many laboratories.Ministerio de Ciencia, Innovación y Universidades (España)Depto. de Química FísicaFac. de Ciencias QuímicasTRUEpu
Measurement of the time-dependent CP asymmetry in B0 -> J/ψ KS0 decays
No full textThis Letter reports a measurement of the CP violation observables SJ/ψK0S and CJ/ψK0S in the decay channel B0→J/ψK0S performed with 1.0 fb−1 of pp collisions at s√=7 TeV collected by the LHCb experiment. The fit to the data yields SJ/ψK0S=0.73±0.07(stat)±0.04(syst) and CJ/ψK0S=0.03±0.09(stat)±0.01(syst). Both values are consistent with the current world averages and within
expectations from the Standard Model
Measurement of the branching fraction
No full textThe B
0
s
→ J/ψK
0
S
branching fraction is measured in a data sample corresponding to 0.41 fb−1
of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to
the penguin contributions affecting the sin 2β measurement from B
0
→ J/ψK
0
S
. The time-integrated
branching fraction is measured to be B(B
0
s
→ J/ψK
0
S
) = (1.83±0.28)×10−5
. This is the most precise
measurement to date
Report on the Engineering and Economic Features of the Pacific Great Eastern Railway:
No full textby J. G. Sullivan
J. D. Brannan letter to Warren G. Harding, January 24, 1921
No full textIn this letter dated January 24, 1921 (the author mistakenly writes 1920), J. D. Brannan at Harvard University Law School to President-elect Warren G. Harding in regards to his choices for cabinet appointments. Brannan recommends Senator Elihu Root for Secretary of State, Charles Evans Hughes for Attorney General, Senator John W. Weeks for Secretary of the Treasury or Secretary of the Navy, and General Leonard Wood for Secretary of War, and includes qualifications for each. After discussing tensions among the government and organized labor leaders, he does not specify an appointment for Secretary of Labor, but includes Herbert Hoover as a qualified candidate.
This letter is part of the Warren G. Harding Papers (MSS 345). This collection includes correspondence, business records, and other materials documenting Harding’s business career as owner and editor-in-chief of The Daily Marion Star, as well as the various stages of his political career. A significant portion of the collection, and what’s available on Ohio Memory, highlights his 1920 presidential campaign, spanning just before publicly announcing his candidacy to handily defeating Ohio Governor James M. Cox in the election. Correspondents include both Ohio and national businessmen, political figures, and ordinary citizens writing with questions, support, congratulatory notes, and campaign advice. Some of the most interesting insights into the tumultuous political climate in the U.S., the extreme factionalism within the Republican Party in Ohio, and Harding’s campaign strategies are described in letters between Harding and his campaign manager, Harry M. Daugherty. Some of the topics addressed include women’s suffrage, Prohibition, the League of Nations, African American representation and issues, and lingering peace negotiations following World War I
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