Search results for "Clusters"
showing 10 items of 1274 documents
Optical active centres in ZnO samples
2006
Abstract In recent years, there has been a resurgence in the interest in the use of ZnO (Eg ∼ 3.37 eV) as a material for a wide range of opto-emitter applications spanning visible and short wavelengths. Bulk, thin films and nanomaterials obtained using different synthesis methods have been investigated for optoelectronic and biotechnological device applications. Nominally undoped bulk samples typically present a myriad-structured near-band-edge recombination, mainly due to free/bound excitons and donor–acceptor pair transitions. Furthermore, deep level emission due to intrinsic defects and extrinsic impurities, such as transition metal ions, are commonly observed in different grades of bulk…
Isomer effects in fragmentation of Polycyclic Aromatic Hydrocarbons
2015
We have observed significant differences in the fragmentation patterns of isomeric Polycyclic Aromatic Hydrocarbon (PAH) cations following collisions with helium atoms at center-of-mass energies around 100 eV. This is in contrast to the situation at other collision energies or in photo-absorption experiments where isomeric effects are very weak and where the lowest-energy dissociation channels (H- and C2H2-loss) domihate in statistical fragmentation processes. In the 100 eV range, non-statistical fragmentation also competes and is uniquely linked to losses of single carbon atoms (CHx-losses). We find that such CHx-losses are correlated with the ionic ground state energy within a given group…
Exploring the atomic structure of 1.8 nm monolayer-protected gold clusters with aberration-corrected STEM
2017
Abstract Monolayer-protected (MP) Au clusters present attractive quantum systems with a range of potential applications e.g. in catalysis. Knowledge of the atomic structure is needed to obtain a full understanding of their intriguing physical and chemical properties. Here we employed aberration-corrected scanning transmission electron microscopy (ac-STEM), combined with multislice simulations, to make a round-robin investigation of the atomic structure of chemically synthesised clusters with nominal composition Au 144 (SCH 2 CH 2 Ph) 60 provided by two different research groups. The MP Au clusters were “weighed” by the atom counting method, based on their integrated intensities in the high …
"Table 34" of "Measurements of Forward Proton Production with Incident Protons and Charged Pions on Nuclear Targets at the CERN Proton Synchroton"
2010
Differential cross section for proton production with a proton beam and Aluminium target in the angular range 0.100 to 0.150 radians. The errors are the square-root of the diagonal elements of the covariant matrix.
"Table 35" of "Measurements of Forward Proton Production with Incident Protons and Charged Pions on Nuclear Targets at the CERN Proton Synchroton"
2010
Differential cross section for proton production with a proton beam and Aluminium target in the angular range 0.150 to 0.200 radians. The errors are the square-root of the diagonal elements of the covariant matrix.
"Table 30" of "Measurements of Forward Proton Production with Incident Protons and Charged Pions on Nuclear Targets at the CERN Proton Synchroton"
2010
Differential cross section for proton production with a positive pion beam and Aluminium target in the angular range 0.100 to 0.150 radians. The errors are the square-root of the diagonal elements of the covariant matrix.
"Table 31" of "Measurements of Forward Proton Production with Incident Protons and Charged Pions on Nuclear Targets at the CERN Proton Synchroton"
2010
Differential cross section for proton production with a positive pion beam and Aluminium target in the angular range 0.150 to 0.200 radians. The errors are the square-root of the diagonal elements of the covariant matrix.
"Table 1" of "Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Soft Electron b-Tagging"
2010
Measured cross section assuming a top quark mass of 175 GeV. The second systematic error is the uncertainty on the luminosity.
"Table 1" of "Measurement of the t anti-t Production Cross Section in 2 fb**-1 of p anti-p Collisions at s**(1/2) =1.96-TeV Using Lepton Plus Jets Ev…
2010
Measured cross section assuming a top quark mass of 175 GeV. The second systematic error is the uncertainty on the luminosity.
"Table 1" of "Measurement of the Top Pair Production Cross Section in the Dilepton Decay Channel in $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.96 TeV"
2010
Measured cross section assuming a top quark mass of 175 GeV. The second systematic error is the uncertainty on the luminosity.