Search results for " clusters"
showing 10 items of 1091 documents
Hydrogen induced metallization of ZnO (11̅00) surface: Ab initio study
2014
Abstract Results of first principles hybrid calculations are presented for hydrogen atoms adsorbed upon non-polar ZnO (1100) surface. The energy of surface atomic relaxation, H adsorption energy, electronic density redistribution and modification of the electronic structure are discussed. It is shown that hydrogen is adsorbed mainly on the surface oxygen ions and forms a strong bonding with them (2.7 eV). Adsorption of hydrogen on the surface zinc ions is energetically unfavorable (− 4.4 eV). It also shown that surface hydrogen atoms are very shallow donors, thus, contributing to the electronic conductivity, and ZnO metallization.
DFT studies on catalytic properties of isolated and carbon nanotube supported Pd9 cluster. Part II. Hydro-isomerization of butene isomers
2010
The processes involved in the butene hydro-isomerization, occurring on a small palladium cluster in the presence of dissociated hydrogen, have been investigated by means of DFT and DFT/MM approaches. This study has been performed both on an isolated (unsupported) Pd(9) cluster and on the same cluster when it is supported on a portion of a single-walled armchair(6,6) carbon nanotube. The study follows another investigation which has already been published concerning the adsorption, fragmentation and diffusion of hydrogen on the same metal cluster. The main aspects involved in the parallel reaction steps of the whole hydro-isomerization mechanisms are not strongly affected by the presence of …
Anharmonicity modeling in hydrogen bonded solvent dimers
2021
Abstract Harmonic and anharmonic frequencies of dimers and mixed dimers of water, methanol and benzene were computed and the results were critically analysed to investigate the anharmonicity of the normal mode vibrations within density functional theory (DFT) with empirically included Grimme correction for dispersion (D3). From several options, the B3LYP-D3/6-31++G* level of theory was selected as a good compromise between accuracy and calculation speed, suitable for future modeling of larger solvent clusters. The obtained raw harmonic and anharmonic second-order perturbation theory of vibrational frequencies (VPT2) were additionally scaled using a two-range procedure (below and above 2000 …
Capturing Hydrophobic Trifluoroiodomethane in Water into an M 4 L 6 Cage
2016
Synthetically important trifluoroiodomethane (CF3I) was trapped in water by using a metal–organic supramolecular anionic cage. Under ambient conditions, nearly 1:1 encapsulation of the hydrophobic, gaseous CF3I substrate with the cage was observed, and its binding constant was calculated by relative comparison with benzene encapsulation.
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.