Author: Amy Leigh Brunsvold Publisher: 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.
Author: Ricardo Diez Muino Publisher: Springer Science & Business Media ISBN: 3642329551 Category : Science Languages : en Pages : 439
Book Description
This book gives a representative survey of the state of the art of research on gas-surface interactions. It provides an overview of the current understanding of gas surface dynamics and, in particular, of the reactive and non-reactive processes of atoms and small molecules at surfaces. Leading scientists in the field, both from the theoretical and the experimental sides, write in this book about their most recent advances. Surface science grew as an interdisciplinary research area over the last decades, mostly because of new experimental technologies (ultra-high vacuum, for instance), as well as because of a novel paradigm, the ‘surface science’ approach. The book describes the second transformation which is now taking place pushed by the availability of powerful quantum-mechanical theoretical methods implemented numerically. In the book, experiment and theory progress hand in hand with an unprecedented degree of accuracy and control. The book presents how modern surface science targets the atomic-level understanding of physical and chemical processes at surfaces, with particular emphasis on dynamical aspects. This book is a reference in the field.
Author: Joe N SMITH (Jr) Publisher: ISBN: Category : Languages : en Pages : 23
Book Description
Research is summarized on molecular-beam scattering experiments performed under well-defined and reproducible surface conditions. The microscopic details of the gas-surface interaction mechanism are discussed.
Author: Leon Trilling Publisher: ISBN: Category : Languages : en Pages : 32
Book Description
In the course of the research program into phenomena related to gas-surface interaction which the authors conducted over the last several years, the broad objective has been to seek answers to the following general question: Given a stream of gas molecules of known properties approaching a specified surface, how does one predict the velocity and flux distributions of the streams which leave the surface. Beginning with very simple configurations, they have attempted to account for an increasingly detailed extended set of properties of the solid surface, of the gas stream and of the interaction process. They have attempted to formulate the basic problem with a view to understanding molecular transport phenomena, first on inert metallic surfaces such as the skins of satellite vehicles in orbital flight, and later on ice crystals and nucleating centers in Brownian motion in the upper atmosphere. They have also begun to study the mechanism of interaction of molecular and atomic oxygen on graphite surfaces.
Author: Amy Leigh Brunsvold
Author: Ricardo Diez Muino
Author: Sam S. Fisher
Author: Howard Saltsburg
Author: J. A. Barker
Author: James Ashton Riley
Author: Joe N SMITH (Jr)
Author: 
Author: Leon Trilling
Author: