Inelastic Scattering and Interference

1997 ◽  
Vol 3 (S2) ◽  
pp. 1033-1034
Author(s):  
D. Van Dyck
Keyword(s):  
Electron Diffraction ◽  
Energy Loss ◽  
Inelastic Scattering ◽  
Energy Exchange ◽  
Position Vector ◽  
Inelastic Electron ◽  
Global System ◽  
Interference Fringes ◽  
Energy Exchanges ◽  
Generating System

Recently it has been a matter of controversy whether inelastically scattered electrons can yield interference fringes so as to obtain holograms, and in particular whether compensation of energy loss in the object by energy gain in the source will maintain coherence [1]. In discussions about coherence (and wave mechanisms in general) it is always dangerous to rely on intuitive arguments (exchange of energy, time of interaction, etc.). In this work we will start from the most general approach, which is inspired by the treatment of inelastic electron diffraction crystals by Yoshioka in 1957 [2]. Energy exchanges are always described quantummechanically by an Hamiltonian. Therefore we can only investigate the balance between energy exchange properly if electron, object, and source are described by one global Hamiltonian. With source we mean the whole electron generating system (emitter, accelerator, condensor).Consider a global system consisting of an electron, with position vector r, an object with particle vectors ri, and a source with particles at rα.

Inelastic Electron-Matter Interactions

1978 ◽  
Vol 36 (3) ◽  
pp. 259-267
Author(s):  
J. Silcox
Keyword(s):  
Electron Microscope ◽  
Energy Loss ◽  
Chemical Structure ◽  
Inelastic Electron ◽  
Primary Concern ◽  
Unique Probe ◽  
Introductory Paper ◽  
Elastic Processes ◽  
Experimental Level ◽  
Inelastic Processes

In this introductory paper, my primary concern will be in identifying and outlining the various types of inelastic processes resulting from the interaction of electrons with matter. Elastic processes are understood reasonably well at the present experimental level and can be regarded as giving information on spatial arrangements. We need not consider them here. Inelastic processes do contain information of considerable value which reflect the electronic and chemical structure of the sample. In combination with the spatial resolution of the electron microscope, a unique probe of materials is finally emerging (Hillier 1943, Watanabe 1955, Castaing and Henri 1962, Crewe 1966, Wittry, Ferrier and Cosslett 1969, Isaacson and Johnson 1975, Egerton, Rossouw and Whelan 1976, Kokubo and Iwatsuki 1976, Colliex, Cosslett, Leapman and Trebbia 1977). We first review some scattering terminology by way of background and to identify some of the more interesting and significant features of energy loss electrons and then go on to discuss examples of studies of the type of phenomena encountered. Finally we will comment on some of the experimental factors encountered.

Quanitative aspects of electron diffraction using electron holography

1995 ◽  
Vol 53 ◽  
pp. 616-617
Author(s):  
E. Völkl ◽  
L.F. Allard ◽  
B. Frost ◽  
T.A. Nolan
Keyword(s):  
Electron Beam ◽  
Electron Diffraction ◽  
Software Package ◽  
Spatial Coherence ◽  
Electron Holography ◽  
Image Intensity ◽  
Interference Fringes ◽  
Complex Image ◽  
The Difference ◽  
Recorded Image

Off-axis electron holography has the well known ability to preserve the complex image wave within the final, recorded image. This final image described by I(x,y) = I(r) contains contributions from the image intensity of the elastically scattered electrons IeI (r) = |A(r) exp (iΦ(r)) |, the contributions from the inelastically scattered electrons IineI (r), and the complex image wave Ψ = A(r) exp(iΦ(r)) as:(1) I(r) = IeI (r) + Iinel (r) + μ A(r) cos(2π Δk r + Φ(r))where the constant μ describes the contrast of the interference fringes which are related to the spatial coherence of the electron beam, and Φk is the resulting vector of the difference of the wavefront vectors of the two overlaping beams. Using a software package like HoloWorks, the complex image wave Ψ can be extracted.

Quantitative energy-filtered electron diffraction

1994 ◽  
Vol 52 ◽  
pp. 992-993
Author(s):  
R. Vincent
Keyword(s):  
Electron Diffraction ◽  
Inelastic Scattering ◽  
Dynamic Range ◽  
Electron Optics ◽  
Surface Layers ◽  
High Brightness ◽  
Inclined Surfaces ◽  
Perfect Symmetry ◽  
Amorphous Surface ◽  
The Ideal

Microanalysis and diffraction on a sub-nanometre scale have become practical in modern TEMs due to the high brightness of field emission sources combined with the short mean free paths associated with both elastic and inelastic scattering of incident electrons by the specimen. However, development of electron diffraction as a quantitative discipline has been limited by the absence of any generalised theory for dynamical inelastic scattering. These problems have been simplified by recent innovations, principally the introduction of spectrometers such as the Gatan imaging filter (GIF) and the Zeiss omega filter, which remove the inelastic electrons, combined with annual improvements in the speed of computer workstations and the availability of solid-state detectors with high resolution, sensitivity and dynamic range.Comparison of experimental data with dynamical calculations imposes stringent requirements on the specimen and the electron optics, even when the inelastic component has been removed. For example, no experimental CBED pattern ever has perfect symmetry, departures from the ideal being attributable to residual strain, thickness averaging, inclined surfaces, incomplete cells and amorphous surface layers.

Le spectre des états électroniques de Kr I mesuré par spectrométrie électronique

1975 ◽  
Vol 53 (19) ◽  
pp. 2079-2084 ◽  
Author(s):  
A. Delage ◽  
J.-D. Carette
Keyword(s):  
Experimental Data ◽  
Energy Loss ◽  
Inelastic Scattering ◽  
Electronic States ◽  
Resolving Power ◽  
Electron Spectrometer ◽  
Energy Incident ◽  
First Time ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra

The spectrum of electronic states of krypton I has been measured by inelastic scattering of monoenergetic electrons with the aid of an electron spectrometer which has a high resolving power, ΔE/E = 0.02. Electron energy loss spectra have allowed us to detect and identify numerous electronic states of krypton I for the first time by the means of this experimental method. The relative heights of the peaks corresponding to an energy loss, which are related to the probability of excitation of the atom by electron impact to a given state, have been measured from experimental data as a function of the energy incident electrons and as a function of the scattering angle.

Founding a Field Theory of Work

2014 ◽  
pp. 34-64
Author(s):  
Raymon R. Bruce
Keyword(s):  
Field Theory ◽  
Organization Development ◽  
Textile Industry ◽  
Energy Exchange ◽  
Stakeholder Management ◽  
Work Organization ◽  
Wicked Problem ◽  
Organization Model ◽  
Energy Exchanges ◽  
Issue Analysis

This chapter traces the origin of the concept of work in five staged sections. The first section examines the question, what is work? Work originally referred to “doing,” that is, work organization, synergy, and energy. The second section develops the Greek word family for work into a dynamic model of doing. The third section shows how nature guides working change through energy exchange. It examines how a work as re-organization model would function in nature's jurisdictional domain of guiding energy exchanges. Nature's laws provide guidance for self-governing latitude to energy jurisdictional domains' evolutionary change. The fourth section examines policymaking as human guidance imitating nature. Policymaking limits individual self-governance to guide a specified social community of people (polis) doing work. Policymaking is explored to see how humans use policymaking to govern themselves and their cultural social groups including governments by using nature's use of laws as guidance. Policymaking is also a form of laying down basic parameters of work as re-organization through energy exchanges in the ambient environment. Policies are human artifacts designed help a social group work well together. Part five presents an issue analysis as an invited Organization Development consultant to help find ways for the Sri Lankan government, the University of Moratuwa, and the apparel and textile industry to work together in their extreme makeover of human resource development of their apparel and textile industry. Action training and research, stakeholder management, and wicked problem issue analysis are the organization development methods used to demonstrate this field theory of work re-organization through energy exchange.

scholarly journals Mapping structure and morphology of amorphous organic thin films by 4D-STEM pair distribution function analysis

Microscopy ◽  
2019 ◽  
Vol 68 (4) ◽  
pp. 301-309 ◽  
Author(s):  
Xiaoke Mu ◽  
Andrey Mazilkin ◽  
Christian Sprau ◽  
Alexander Colsmann ◽  
Christian Kübel
Keyword(s):  
Distribution Function ◽  
Electron Diffraction ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Pair Distribution Function ◽  
Phase Distribution ◽  
Function Analysis ◽  
New Approach ◽  
Electron Energy Loss

Abstract Imaging the phase distribution of amorphous or partially crystalline organic materials at the nanoscale and analyzing the local atomic structure of individual phases has been a long-time challenge. We propose a new approach for imaging the phase distribution and for analyzing the local structure of organic materials based on scanning transmission electron diffraction (4D-STEM) pair distribution function analysis (PDF). We show that electron diffraction based PDF analysis can be used to characterize the short- and medium-range order in aperiodically packed organic molecules. Moreover, we show that 4D-STEM-PDF does not only provide local structural information with a resolution of a few nanometers, but can also be used to image the phase distribution of organic composites. The distinct and thickness independent contrast of the phase image is generated by utilizing the structural difference between the different types of molecules and taking advantage of the dose efficiency due to use of the full scattering signal. Therefore, this approach is particularly interesting for imaging unstained organic or polymer composites without distinct valence states for electron energy loss spectroscopy. We explore the possibilities of this new approach using [6,6]-phenyl-C61- butyric acid methyl ester (PC61BM) and poly(3-hexylthiophene-2,5-diyl) (P3HT) as the archetypical and best-investigated semiconductor blend used in organic solar cells, compare our phase distribution with virtual dark-field analysis and validate our approach by electron energy loss spectroscopy.

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