Threshold behavior for chemical reactions: line-of-centers cross section for silicon(1+)(2P) + molecular hydrogen .fwdarw. silicon hydride(1+) (SiH+) + atomic hydrogen

1984 ◽  
Vol 88 (23) ◽  
pp. 5454-5456 ◽  
Author(s):  
J. L. Elkind ◽  
P. B. Armentrout
Keyword(s):  
Cross Section ◽  
Chemical Reactions ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Threshold Behavior ◽  
Silicon Hydride

Photodissociation of H2 near Threshold Energies

1970 ◽  
Vol 25 (2) ◽  
pp. 237-242 ◽  
Author(s):  
F. J. Comes ◽  
U. Wenning
Keyword(s):  
Electric Field ◽  
Cross Section ◽  
Configuration Interaction ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Hydrogen Atoms ◽  
Dissociation Cross Section ◽  
Excited Molecules ◽  
Threshold Energies ◽  
Near Threshold

Abstract Measurements of the atomic hydrogen fluorescence (Lyα) yield important information on the dissociation behavior of molecular hydrogen under photon impact. Under certain assumptions the dissociation cross section of the molecule can be deduced from such experiments. By applying an appropriate electric field in the observation region those dissociations leading to the formation of metastable hydrogen atoms can be quantitatively determined. This information opens the possibility to describe the predissociation of the excited H2-molecules in the C-, D-and B″-states. The experiments show that the excited molecules in these particular states dissociate into H(1S) and H(2S) by configuration interaction with the B′-state.

Threshold Behavior of then=2Excitation Cross Section in Atomic Hydrogen

1966 ◽  
Vol 17 (15) ◽  
pp. 800-802 ◽  
Author(s):  
P. G. Burke ◽  
S. Ormonde ◽  
W. Whitaker
Keyword(s):  
Cross Section ◽  
Atomic Hydrogen ◽  
Threshold Behavior

Ionization of atomic hydrogen by protons in the energy range 60 to 400 keV

1964 ◽  
Vol 277 (1368) ◽  
pp. 137-141 ◽  
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Born Approximation ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Low Energy ◽  
Absolute Cross Section ◽  
Energy Data ◽  
Beam Technique ◽  
Good Agreement

Ionization of atomic hydrogen by protons has been investigated by means of the ‘crossed beam ’ technique in which a proton beam from a Van de Graaff accelerator was arranged to intersect a modulated beam of atomic hydrogen produced from a furnace source. The ratio of the cross-section for ionization of atomic hydrogen to that for molecular hydrogen was determined by comparing the signals due to electrons arising from the interaction region when the beam was mainly atomic and when the beam was entirely molecular. The absolute cross-section for ionization of atomic hydrogen by protons was determined from a knowledge of the molecular cross-section. The results are in good agreement with the Born approximation calculations of Bates & Grilling and in fair agreement with the recent low energy data of Fite, Stebbings, Hummer & Brackmann.

The Design and Simulation for a Novel Electroosmotic Micromixer

2006 ◽  
Author(s):  
Hongjun Song ◽  
Xie-Zhen Yin ◽  
Dawn J. Bennett
Keyword(s):  
Electric Field ◽  
Cross Section ◽  
Chemical Reactions ◽  
Electroosmotic Flow ◽  
Chaotic Advection ◽  
Microfluidic Systems ◽  
Mixing Effect ◽  
Passive Mixers ◽  
The Cross ◽  
External Forces

The analysis of fluid mixing in microfluidic systems is useful for many biological and chemical applications at the micro scale such as the separation of biological cells, chemical reactions, and drug delivery. The mixing of fluids is a very important factor in chemical reactions and often determines the reaction velocity. However, the mixing of fluids in microfluidics tends to be very slow, and thus the need to improve the mixing effect is a critical challenge for the development of the microfluidic systems. Micromixers can be classified into two types, active micromixers and passive micromixers. Passive micromixers depend on changing the structure and shape of microchannels in order to generate chaotic advection and to increase the mixing area. Thus, the mixing effect is enhanced without any help from external forces. Although passive micromixers have the advantage of being easily fabricated and requiring no external energy, there are also some disadvantages. For example, passive mixers often lack flexibility and power. Passive mixers rely on the geometrical properties of the channel shapes to induce complicated fluid particle trajectories thereby enhancing the mixing effect. On the other hand, active micromixers induce a time-dependent perturbation in the fluid flow. Active micromixers mainly use external forces for mixing including ultrasonic vibration, dielectrophoresis, magnetic force, electrohydrodynamic, and electroosmosis force. However, the complexity of their fabrication limits the application of active micromixers. In this paper we present a novel electroosmotic micromixer using the electroosmotic flow in the cross section to enhance the mixing effect. A DC electric field is applied to a pair of electrodes which are placed at the bottom of the channel. A transverse flow is generated in the cross section due to electroosmotic flow. Numerical simulations are investigated using a commercial software Fluent® which demonstrates how the device enhances the mixing effect. The mixing effect is increased when the magnitude of the electric field increased. The influences of Pe´clet number are also discussed. Finally, a simple fabrication using polymeric materials such as SU-8 and PDMS is presented.

Further investigations of charge exchange and electron detachment - I. Ion energies 3 to 40 keV - II. Ion energies 100 to 4000 eV

1955 ◽  
Vol 227 (1171) ◽  
pp. 466-486 ◽  
Keyword(s):  
Charge Transfer ◽  
Energy Range ◽  
Cross Sections ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Hydrogen Ions ◽  
Electron Detachment ◽  
Rare Gases ◽  
Helium Ions ◽  
Ion Energies

This paper describes the measurement of charge transfer cross-sections for protons, molecular hydrogen ions and helium ions in the rare gases and hydrogen, and electron detachment cross-sections for negative atomic hydrogen ions in the rare gases. Part I describes the energy range 3 to 40 keV. In part II the energy range 100 to 4000 eV is described, and the results are discussed in terms of the pseudo-adiabatic hypothesis. Comparisons are made with other experimental results, and anomalous molecular cases are discussed in terms of reactions involving anti-bonding states.

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