scholarly journals Reactive Bimolecular Collisions Studied With Combined Pulsed Lasers and Pulsed, Crossed, Supersonic Molecular Beams

1990 ◽  
Vol 10 (5-6) ◽  
pp. 367-376 ◽  
Author(s):  
M. Costes ◽  
C. Naulin ◽  
G. Dorthe ◽  
Z. Moudden
Keyword(s):  
Molecular Beam ◽  
Collision Energy ◽  
Ultra Violet ◽  
Molecular Beams ◽  
High Signal ◽  
Pulsed Lasers ◽  
Laser Induced Fluorescence Detection ◽  
Supersonic Molecular Beams ◽  
Molecular Reaction ◽  
Bimolecular Collisions

Pulsed, supersonic molecular beams and pulsed lasers are particularly well matched tools when combined in molecular reaction dynamics studies. Salient features of an experiment using two pulsed molecular beam sources, a pulsed ultra-violet laser for creating reactive atoms by laser ablation and a pulsed dye laser for performing laser-induced fluorescence detection of the products are described. Differences with steady-state molecular beam experiments are outlined with respect to the following points: facility of inverting the data, possibility of obtaining high signal-to-background ratios and wide ranges of collision energy. These points are illustrated with some results concerning the reactions:C(n3P)J + NO(Xπr2)→ CN(X2Σ2) + O(n3PJ),C(n3PJ) + N2O(X1Σ+) →CN(X2Σ+) + NO(Xπr2)and Mg(n1S0) + N2O(X1Σ+) →MgO(X1Σ+) + N2(X1Σg+)

Calibration of a Slotted Disk Velocity Selector Using Supersonic Molecular Beams

1971 ◽  
Vol 26 (10) ◽  
pp. 1634-1638 ◽  
Author(s):  
P. Cantini ◽  
M. G. Dondi ◽  
F. Torello
Keyword(s):  
Velocity Distribution ◽  
Room Temperature ◽  
Molecular Beam ◽  
Molecular Beams ◽  
Calibration Method ◽  
Theoretical Distribution ◽  
Experimental Procedure ◽  
Supersonic Molecular Beam ◽  
Supersonic Molecular Beams ◽  
Velocity Scale

Abstract A new calibration method for slotted disk velocity selectors is presented and is compared with other calibration procedures. It is based on the measurement of the velocity distribution of a supersonic molecular beam produced by a room temperature source. The error due to the assumed theoretical distribution and to experimental procedure is discussed. It is shown that the velocity scale is known to within 0.8%.

scholarly journals Synthesis of single layer graphene on Cu(111) by C60 supersonic molecular beam epitaxy

RSC Advances ◽  
2016 ◽  
Vol 6 (44) ◽  
pp. 37982-37993 ◽  
Author(s):  
Roberta Tatti ◽  
Lucrezia Aversa ◽  
Roberto Verucchi ◽  
Emanuele Cavaliere ◽  
Giovanni Garberoglio ◽  
...  
Keyword(s):  
Kinetic Energy ◽  
Molecular Beam ◽  
Materials Science ◽  
Single Layer ◽  
Molecular Beams ◽  
Single Layer Graphene ◽  
Physical Processes ◽  
Supersonic Molecular Beam ◽  
Layer Graphene ◽  
High Kinetic Energy

High kinetic energy impacts between inorganic surfaces and molecular beams seeded by organics represent a fundamental tool in materials science, particularly when they activate chemical–physical processes leading to nanocrystals' growth.

Observations of TiO2 Surfaces Using Totally Reflected X-ray In-plane Diffraction Under UV Irradiation

2002 ◽  
Vol 751 ◽  
Author(s):  
T. Horiuchi ◽  
H. Ochi ◽  
K. Kaisei ◽  
K. Ishida ◽  
K. Matsushige
Keyword(s):  
Uv Irradiation ◽  
Uv Light ◽  
Plane Surface ◽  
Signal To Noise Ratio ◽  
High Surface ◽  
Ultra Violet ◽  
High Signal ◽  
X Ray ◽  
Force Microscopy ◽  
Catalytic Activities

ABSTRACTSurface lattice displacements of titanium dioxide (TiO2: rutile) during ultra-violet (UV) light irradiation have been investigated using a total reflection x-ray diffraction, which provides a high signal to noise ratio (S/N) and superior in-plane surface diffraction. Under the environments in vapors of H2O, CH3OH, C2H5OH and C3H6OH, the photo-catalytic activities of TiO2 (110), (100) and (001) surfaces subject to UV irradiation have been measured. It is found that the diffraction peaks and their full width half maxima (FWHMs) show some peculiarities with respect to the photo-catalytic activities in both surface lattices and adsorbed molecules in vapors. Furthermore, Kelvin force microscopy (KFM) has showed that there exists a very high surface potential, probably due to surface atom displacements induced by UV irradiation. With regard to the origin of the photo-catalytic activities, the induced surface potentials are discussed.

Low Interface State Density Oxide-GaAs Structures Fabricated by In-Situ Molecular Beam Epitaxy

1996 ◽  
Vol 421 ◽  
Author(s):  
M. Passlack ◽  
M. Hong
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Molecular Beams ◽  
Interface State ◽  
State Density ◽  
Interface State Density ◽  
In Situ Deposition ◽  
Interface Recombination Velocity ◽  
Recombination Velocity

AbstractWe have extended the spectrum of molecular-beam epitaxy (MBE) related techniques by introducing in-situ deposition of oxides. The oxide films have been deposited on clean, atomically ordered (100) GaAs wafer surfaces using molecular beams of gallium-, magnesium-, silicon-, or aluminum oxide. Among the fabricated oxide-GaAs heterostructures, Ga2O3-GaAs interfaces exhibit unique electronic properties including an interface state density Dit in the low 1010 cm−2eV−1 range and an interface recombination velocity S of 4000 cm/s. The formation of inversion layers in both n- and p-type GaAs has been clearly established. Further, thermodynamic and photochemical stability of excellent electronic interface properties of Ga2O3-GaAs structures has been demonstrated.

Self-Assembled GaAs Quantum Rings by MBE Droplet Epitaxy

2007 ◽  
Vol 121-123 ◽  
pp. 541-544
Author(s):  
She Song Huang ◽  
Zhi Chuan Niu ◽  
Jian Bai Xia
Keyword(s):  
Molecular Beam ◽  
Single Photon ◽  
Photon Emission ◽  
Molecular Beams ◽  
Semiconductor Nanostructures ◽  
Droplet Epitaxy ◽  
Single Photon Emission ◽  
Quantum Rings ◽  
Atomic Force ◽  
Surface Migration

Fabrication of semiconductor nanostructures such as quantum dots (QDs), quantum rings (QRs) has been considered as the important step for realization of solid state quantum information devices, including QDs single photon emission source, QRs single electron memory unit, etc. To fabricate GaAs quantum rings, we use Molecular Beam Epitaxy (MBE) droplet technique in this report. In this droplet technique, Gallium (Ga) molecular beams are supplied initially without Arsenic (As) ambience, forming droplet-like nano-clusters of Ga atoms on the substrate, then the Arsenic beams are supplied to crystallize the Ga droplets into GaAs crystals. Because the morphologies and dimensions of the GaAs crystal are governed by the interplay between the surface migration of Ga and As adatoms and their crystallization, the shape of the GaAs crystals can be modified into rings, and the size and density can be controlled by varying the growth temperatures and As/Ga flux beam equivalent pressures(BEPs). It has been shown by Atomic force microscope (AFM) measurements that GaAs single rings, concentric double rings and coupled double rings are grown successfully at typical growth temperatures of 200°C to 300°C under As flux (BEP) of about 1.0×10-6 Torr. The diameter of GaAs rings is about 30-50 nm and thickness several nm.

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