Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Molecular Beam Studies of Atomic Oxygen
Author: A Hypersonic Atomic Oxygen Molecular Beam Source
Author: Calvin K. LamPublisher:
ISBN:
Category : Molecular beams
Languages : en
Pages : 110
Book Description
Crossed Molecular Beam Studies of Ground State Oxygen Atom Reactions
Author: Martin Philip HallMolecular Beam Studies of Oxygen Atom Reactions with Unsaturated Hydrocarbons
Author: Annemarie SchmoltnerPublisher:
ISBN:
Category :
Languages : en
Pages : 628
Book Description
Molecular Beam Studies of Hyperthermal Atomic Oxygen and Argon Interactions with Polymer Surfaces and Gas-phase Molecules
Author: Amy Leigh BrunsvoldPublisher:
ISBN:
Category :
Languages : en
Pages : 215
Book Description
O atoms and N2 molecules in the outer atmosphere of the Earth collide with spacecraft surfaces and various gases that are released from space vehicles. The high relative velocity of the collisions promotes high reaction probability and large energy transfers, leading to materials degradation and chemiluminescent reactions, which may interfere with the mission of the vehicle. The work presented in this thesis uses sophisticated molecular beam and surface science techniques to study materials degradation and individual reactive and inelastic collisions in an effort to understand the complex chemistry and physics that are characteristic of space vehicle interactions with Earth's upper atmosphere. A new space-durable polymer, polyhedral oligomeric silsesquioxane polyimide, has been identified. When exposed to atomic oxygen, this polymer forms a protective SiO2 layer on its surface. Beam-surface scattering experiments showed that collision-induced dissociation becomes an important gas-surface process when the translational energy of the incident atom or molecule is greater than 8 eV. Experiments on the dynamics of gas-phase collisions at hyperthermal collision energies found that inelastic collisions may transfer large amounts of energy into internal degrees of freedom. The scattering dynamics of the reactive 16OC product from the 16O( 3P) + C18O → 16OC + 18O reaction were quite unexpected, with 16OC predominantly forward scattered. Experiments on the reactions of O( 3P) with H2O demonstrated the occurrence of a previously unobserved reaction pathway, O(3P) + H2O → HO2 + H, with a barrier determined to be ∼2.6 eV. These studies of hyperthermal processes with molecular beam techniques have enabled us to identify a promising new material and to understand the detailed collision dynamics in model gas-surface and gas-phase systems. In each case, the experiments have revealed new chemical or energy transfer processes that were not considered earlier. These previously unknown processes reveal trends in hyperthermal collisions that will undoubtedly be critical to the planning and design of missions that put space vehicles in contact with the outer reaches of the Earth's atmosphere.
Crossed Beam Reactive Scattering of Oxygen Atoms and Surface Scattering Studies of Gaseous Condensation
Author: Steven Jay SibenerDevelopment of a Nozzle Beam Containing Atomic Oxygen
Author: Calvin K. LamPublisher:
ISBN:
Category : Molecular beams
Languages : en
Pages : 47
Book Description
Initial studies of the feasibility of producing a hypersonic molecular beam containing appreciable amount of atomic oxygen have been successfully completed. The purpose of the work was to produce a molecular beam which could be used for basic and applied studies related to the interaction of the earth's upper atmosphere, such as accommodation coefficient measurements or surface reactions at high kinetic energy. A quartz tube source was developed for the molecular beam in which a 200 watt microwave discharge could be maintained. The studies included the effect of pressure and orifice size, for which a compromise was involved in order to achieve high Mach numbers and high dissociation levels, the use of double cavities, and the effect of small additions of H2O. It was demonstrated in these initial tests that a hypersonic beam from a 92% He 8% O2 mixture could be produced with 17% dissociation. (Author).
Atomic and Molecular Beams
Author: Cyril Bernard LucasPublisher: CRC Press
ISBN: 1466561068
Category : Science
Languages : en
Pages : 374
Book Description
Atomic and molecular beams are employed in physics and chemistry experiments and, to a lesser extent, in the biological sciences. These beams enable atoms to be studied under collision-free conditions and allow the study of their interaction with other atoms, charged particles, radiation, and surfaces. Atomic and Molecular Beams: Production and Col
Crossed Molecular Beam Studies of Atmospheric Chemical Reaction Dynamics
Author: Jingsong ZhangCrossed Molecular Beam Study of the Reactions of Oxygen Atoms and Free Radicals
Author: Yuan Tseh LeePublisher:
ISBN:
Category :
Languages : en
Pages : 11
Book Description
The development of rare gas seeded fluorine atom beam source and reactions studied by this new source are main subject of this brief final report. F+CH3I to IF + CH3 reaction has been studied.