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Book Femtosecond Electron Diffraction Studies of Strongly driven Structural Phase Transitions microform

Download or read book Femtosecond Electron Diffraction Studies of Strongly driven Structural Phase Transitions microform written by Bradley John Siwick and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2004 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The new technique of femtosecond electron diffraction is developed and applied to the study of an ultrafast structural phase transition. A combination of numerical and analytical modeling is used to obtain a comprehensive understanding of the space-charge dominated propagation dynamics of high number density femtosecond electron pulses and to design a novel photoactivated electron gun. This electron source, capable of producing sub-500 femtosecond electron pulses with sufficient brightness to allow the study of even irreversible structural dynamics, is employed to investigate the strongly driven, laser-induced solid-to-liquid phase transition in polycrystalline aluminum. We are able to see, in real time, the loss of the long-range order present in the crystalline phase and the emergence of the liquid structure where only short-range atomic correlations are present; this transition occurs in 3.5 ps for thin-film aluminum with an excitation fluence of 70 mJ/cm2. The sensitivity and temporal resolution was sufficient to capture the time-dependent atomic pair correlation function as the material evolved from the solid to liquid state. These observations provide an atomic level description of the melting process in which the dynamics are best understood as a thermal phase transition under strongly driven conditions.

Book Phase Transitions in Surface Films 2

Download or read book Phase Transitions in Surface Films 2 written by H. Taub and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advanced Study Institute (AS I) entitled "Phase Transitions in Surface Films" was held at the Ettore Majorana Centre for Scientific Culture in Erice, Sicily from June 19 to June 29, 1990. It reviewed the present understanding (experimental and theoretical) of phase transitions of surfaces, interfaces, and thin ftlms as well as the related structural and dynamical properties of these systems. From its inception, this ASI was envisioned as a sequel to one of the same title organized eleven years earlier by J. G. Dash and J. Ruvalds which was also held at the Ettore Majorana Centre. The previous ASI reflected the progress which had been made in understanding quasi two-dimensional (2D) states of matter, particularly adsorbed monolayers, and the phase transitions which occur in them. At that time, the field was barely ten years old. The modern field to which we are referring here can be traced to the landmark experiments of A. Thorny and X. Duval. Beginning in 1967, they published a series of papers presenting evidence from vapor pressure measurements of 2D phases of krypton and other gases adsorbed on polycrystalline (exfoliated) graphite. Their work led to a large number of thermodynamic and scattering experiments on physisorbed ftlms. This in turn motivated a great deal of theoretical interest in 2D systems and their phase transitions.

Book American Doctoral Dissertations

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1997 with total page 806 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Dissertation Abstracts International

Download or read book Dissertation Abstracts International written by and published by . This book was released on 1998 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Physical Review

Download or read book Physical Review written by and published by . This book was released on 1993-07 with total page 1652 pages. Available in PDF, EPUB and Kindle. Book excerpt: Publishes papers that report results of research in statistical physics, plasmas, fluids, and related interdisciplinary topics. There are sections on (1) methods of statistical physics, (2) classical fluids, (3) liquid crystals, (4) diffusion-limited aggregation, and dendritic growth, (5) biological physics, (6) plasma physics, (7) physics of beams, (8) classical physics, including nonlinear media, and (9) computational physics.

Book Physics Briefs

Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1334 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Development of an Ultrafast Low Energy Electron Diffraction Setup

Download or read book Development of an Ultrafast Low Energy Electron Diffraction Setup written by Max Gulde and published by Springer. This book was released on 2015-05-26 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an Ultrafast Low-Energy Electron Diffraction (ULEED) system that reveals ultrafast structural changes on the atomic scale. The achievable temporal resolution in the low-energy regime is improved by several orders of magnitude and has enabled the melting of a highly-sensitive, molecularly thin layer of a polymer crystal to be resolved for the first time. This new experimental approach permits time-resolved structural investigations of systems that were previously partially or totally inaccessible, including surfaces, interfaces and atomically thin films. It will be of fundamental importance for understanding the properties of nanomaterials so as to tailor their properties.

Book Heat Capacity Studies of Surface and Dimensional Effects on the Liquid hexatic Transition in Free standing Liquid crystal Films

Download or read book Heat Capacity Studies of Surface and Dimensional Effects on the Liquid hexatic Transition in Free standing Liquid crystal Films written by Robert Eugene Geer and published by . This book was released on 1991 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1989 with total page 984 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Reflection High Energy Electron Diffraction and Reflection Electron Imaging of Surfaces

Download or read book Reflection High Energy Electron Diffraction and Reflection Electron Imaging of Surfaces written by P.K. Larsen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the papers presented at the NATO Advanced Research Workshop in "Reflection High Energy Electron Diffraction and Reflection Electron Imaging of Surfaces" held at the Koningshof conference center, Veldhoven, the Netherlands, June 15-19, 1987. The main topics of the workshop, Reflection High Energy Electron Diffraction (RHEED) and Reflection Electron Microscopy (REM), have a common basis in the diffraction processes which high energy electrons undergo when they interact with solid surfaces at grazing angles. However, while REM is a new technique developed on the basis of recent advances in transmission electron microscopy, RHEED is an old method in surface crystallography going back to the discovery of electron diffraction in 1927 by Davisson and Germer. Until the development of ultra high vacuum techniques in the 1960's made instruments using slow electrons more accessable, RHEED was the dominating electron diffraction technique. Since then and until recently the method of Low Energy Electron Diffraction (LEED) largely surpassed RHEED in popularity in surface studies. The two methods are closely related of course, each with its own specific advantages. The grazing angle geometry of RHEED has now become a very useful feature because this makes it ideally suited for combination with the thin growth technique of Molecular Beam Epitaxy (MBE). This combination allows in-situ studies of freshly grown and even growing surfaces, opening up new areas of research of both fundamental and technological importance.

Book Electron Diffraction

Download or read book Electron Diffraction written by Richard Beeching and published by . This book was released on 1936 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Instrumentation Development for Interfacial Studies and Analysis of Substrate supported Molecular Thin Films by Reflection High energy Electron Diffraction

Download or read book Instrumentation Development for Interfacial Studies and Analysis of Substrate supported Molecular Thin Films by Reflection High energy Electron Diffraction written by Karjini Rajagopal and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical and physical properties at interfaces play key roles in understanding a number of diverse phenomena. A better molecular-level understanding of the interfacial interactions is needed to utilize them in the potential applications. Different surface-analysis techniques have their own distinct level of surface sensitivity and probe different surface characteristics of the system of interest. Our interest is to directly visualize the structure of atoms and molecules at interfaces of the substrate-supported molecular thin films using reflective high-energy electron diffraction (RHEED). The shorter wavelength of an electron compared to typical bond lengths and its larger scattering cross section make it ideal for surface and interfacial probing. Interfacial behaviors in structure, interactions, phase transition, and thermal evolution of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][Tf2N]) vapor deposited ionic liquid (IL) thin films on substrate surfaces such as highly oriented pyrolytic graphite (HOPG), Hydrogen terminated Si(111), mica, Cu(111) and Ni(111) were studied. By comparing the ordered structural behavior of 3 nm thick [EMIM][Tf2N] film on HOPG with other surfaces, it is found that the terrace surface morphology of HOPG plays a role as a template for vertical stacking of IL ion pairs. The phase transition of [EMIM][Tf2N] on HOPG happened at 256 K, which matches with the melting point of bulk [EMIM][Tf2N] IL. The desorption of 3 nm [EMIM][Tf2N] IL from substrate happened starting from 340 - 360 K to ~ 375 K. As a second system, the interfacial structural ordering of water molecules on cadmium telluride (CdTe(111)A) surface and oxidized CdTe(111)A surface was investigated. A molecular beam doser system was developed to deposit the water molecules in a controlled and quantitative way. On CdTe(111)A surface, the deposited water molecules became ordered ice crystallites by adopting the geometry of the underlying substrate as evidenced by the Bragg diffraction spots. On oxidized CdTe(111)A surface upon deposition, initially formed amorphous water layer turned into Debye–Scherrer diffraction rings indicating the randomly oriented ice crystallites of cubic ice form. From the studies of both systems, the main role of the supported substrate in the ordering of molecules at the interface is found.