Unimolecular decomposition in the sputtering of metal clusters

1992 ◽  
Vol 46 (8) ◽  
pp. 4855-4864 ◽  
Author(s):  
A. Wucher ◽  
B. J. Garrison
Keyword(s):  
Metal Clusters ◽  
Unimolecular Decomposition

Production and STEM examination of controlled-size silver clusters

1983 ◽  
Vol 41 ◽  
pp. 338-339
Author(s):  
M. A. Listvan ◽  
R. P. Andres
Keyword(s):  
Cluster Size ◽  
Metal Clusters ◽  
Experimental Parameter ◽  
Carbon Films ◽  
Metal Species ◽  
Silver Clusters ◽  
Free Jet ◽  
Size Dependent ◽  
Cluster Properties ◽  
Controllable Size

Knowledge of the function and structure of small metal clusters is one goal of research in catalysis. One important experimental parameter is cluster size. Ideally, one would like to produce metal clusters of regulated size in order to characterize size-dependent cluster properties.A source has been developed which is capable of producing microscopic metal clusters of controllable size (in the range 5-500 atoms) This source, the Multiple Expansion Cluster Source, with a Free Jet Deceleration Filter (MECS/FJDF) operates as follows. The bulk metal is heated in an oven to give controlled concentrations of monomer and dimer which were expanded sonically. These metal species were quenched and condensed in He and filtered to produce areosol particles of a controlled size as verified by mass spectrometer measurements. The clusters were caught on pre-mounted, clean carbon films. The grids were then transferred in air for microscopic examination. MECS/FJDF was used to produce two different sizes of silver clusters for this study: nominally Ag6 and Ag50.

Short Communication: Synthesis of Polymer-Embedded Metal Clusters by Thermolysis of Mercaptides—Polymer Blends

Polymer News ◽  
2005 ◽  
Vol 30 (9) ◽  
pp. 296-300
Author(s):  
F. Esposito ◽  
V. Casuscelli ◽  
M. V. Volpe ◽  
G. Carotenuto ◽  
L. Nicolais
Keyword(s):  
Polymer Blends ◽  
Short Communication ◽  
Metal Clusters ◽  
Communication Synthesis

Structural reconstruction of germanosilicate frameworks by controlled hydrogen reduction

2019 ◽  
Vol 55 (13) ◽  
pp. 1883-1886 ◽  
Author(s):  
Yue Ma ◽  
Hao Xu ◽  
Xue Liu ◽  
Mingming Peng ◽  
Wenting Mao ◽  
...  
Keyword(s):  
Metal Clusters ◽  
Hydrogen Reduction ◽  
Hydrogen Atmosphere ◽  
Water Washing

Calcined UTL-type germanosilicate was firstly reduced in a hydrogen atmosphere at an appropriate temperature. Then, air-calcination and water-washing procedures were performed to remove the Ge metal clusters or crystals originated from the reduction of skeleton germanium(iv) to yield pure zeolite phase of two daughter structures analogous to IPC-2 and IPC-6.

scholarly journals Direct Kinetic Measurements and Master Equation Modelling of the Unimolecular Decomposition of Resonantly-Stabilized CH2CHCHC(O)OCH3 Radical and an Upper Limit Determination for CH2CHCHC(O)OCH3 + O2 Reaction

2020 ◽  
Vol 234 (7-9) ◽  
pp. 1251-1268 ◽  
Author(s):  
Satya Prakash Joshi ◽  
Prasenjit Seal ◽  
Timo Theodor Pekkanen ◽  
Raimo Sakari Timonen ◽  
Arrke J. Eskola
Keyword(s):  
Master Equation ◽  
Density Functional ◽  
Rate Coefficient ◽  
Decomposition Kinetics ◽  
Basis Sets ◽  
Stationary Points ◽  
Unimolecular Decomposition ◽  
Kinetic Measurements ◽  
Point Energy ◽  
Upper Limit

AbstractMethyl-Crotonate (MC, (E)-methylbut-2-enoate, CH3CHCHC(O)OCH3) is a potential component of surrogate fuels that aim to emulate the combustion of fatty acid methyl ester (FAME) biodiesels with significant unsaturated FAME content. MC has three allylic hydrogens that can be readily abstracted under autoignition and combustion conditions to form a resonantly-stabilized CH2CHCHC(O)OCH3 radical. In this study we have utilized photoionization mass spectrometry to investigate the O2 addition kinetics and thermal unimolecular decomposition of CH2CHCHC(O)OCH3 radical. First we determined an upper limit for the bimolecular rate coefficient of CH2CHCHC(O)OCH3 + O2 reaction at 600 K (k ≤ 7.5 × 10−17 cm3 molecule−1 s−1). Such a small rate coefficient suggest this reaction is unlikely to be important under combustion conditions and subsequent efforts were directed towards measuring thermal unimolecular decomposition kinetics of CH2CHCHC(O)OCH3 radical. These measurements were performed between 750 and 869 K temperatures at low pressures (<9 Torr) using both helium and nitrogen bath gases. The potential energy surface of the unimolecular decomposition reaction was probed at density functional (MN15/cc-pVTZ) level of theory and the electronic energies of the stationary points obtained were then refined using the DLPNO-CCSD(T) method with the cc-pVTZ and cc-pVQZ basis sets. Master equation simulations were subsequently carried out using MESMER code along the kinetically important reaction pathway. The master equation model was first optimized by fitting the zero-point energy corrected reaction barriers and the collisional energy transfer parameters $\Delta{E_{{\text{down}},\;{\text{ref}}}}$ and n to the measured rate coefficients data and then utilize the constrained model to extrapolate the decomposition kinetics to higher pressures and temperatures. Both the experimental results and the MESMER simulations show that the current experiments for the thermal unimolecular decomposition of CH2CHCHC(O)OCH3 radical are in the fall-off region. The experiments did not provide definite evidence about the primary decomposition products.

Insights into oxygen activation on metal clusters for catalyst design

2021 ◽  
Author(s):  
LiXin Chen ◽  
Zi Wen ◽  
Zhi Wen Chen ◽  
Qing Jiang ◽  
Chandra Veer Singh
Keyword(s):  
Metal Clusters ◽  
Aerobic Oxidation ◽  
Oxygen Activation ◽  
Vital Role ◽  
Catalyst Design ◽  
Activation Mechanism ◽  
Oxidation Reactions

The activation mechanism of O2 molecules plays a vital role in the development of catalysts for aerobic oxidation reactions. To gain insights into the activation mechanism of O2, the square...

scholarly journals Infrared action spectroscopy of nitrous oxide on cationic gold and cobalt clusters

2021 ◽  
Vol 23 (1) ◽  
pp. 329-338
Author(s):  
Ethan M. Cunningham ◽  
Alice E. Green ◽  
Gabriele Meizyte ◽  
Alexander S. Gentleman ◽  
Peter W. Beardsmore ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Metal Clusters ◽  
Cobalt Clusters ◽  
Action Spectroscopy ◽  
Infrared Multiple Photon Dissociation ◽  
Cationic Gold

Infrared multiple-photon dissociation spectroscopy reveals the nature of nitrous oxide binding to metal clusters.

A vibrational spectroscopic and computational study of the structures of protonated imidacloprid and its fragmentation products in the gas phase

2021 ◽  
Vol 23 (5) ◽  
pp. 3377-3388
Author(s):  
Kelsey J. Menard ◽  
Jonathan Martens ◽  
Travis D. Fridgen
Keyword(s):  
Computational Chemistry ◽  
Gas Phase ◽  
Vibrational Spectroscopy ◽  
Computational Study ◽  
Unimolecular Decomposition ◽  
Decomposition Products

Vibrational spectroscopy and computational chemistry studies were combined with the aim of elucidating the structures of protonated imidacloprid (pIMI), and its unimolecular decomposition products.

Competitive adsorption of phenol and toluene onto silica-supported transition metal clusters for biofuel purification

2021 ◽  
Author(s):  
Saber Gueddida ◽  
Michael Badawi ◽  
Tejraj Aminabhavi ◽  
Sébastien Lebègue
Keyword(s):  
Transition Metal ◽  
Competitive Adsorption ◽  
Metal Clusters ◽  
Hydrocarbon Fuel ◽  
Energy Performance ◽  
Transition Metal Clusters ◽  
Gas Emissions ◽  
Toxic Gas

Biomass-based renewable hydrocarbon fuel is a complex mix that contains many oxygenating substances, in particular phenolics, which leads to adverse consequences such as reduced engine energy performance and increased toxic gas emissions.

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