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A tensorial Green-function treatment of the electronic transmission properties of an atomic wire T-junction is presented within the framework of the tight-binding approximation. The adoption of the tensorial formalism enables overlap effects to be included in a straightforward manner, without the ne...
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The electronic structure of quasiperiodic lattices is studied. An alloy theory, including short-range order effects, is used to approximate Fibonacci and Thue–Morse lattices. Short-range order is treated by embedding small clusters in an alloy that itself incorporates a two-site approximation, and...
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A dynamical-systems model of plasma glucose concentration, andits regulation by insulin and glucagon, is described, as pertains to types 1 and2 diabetes. The hyperglycemic case is seen to be dependent only on insulinconcentration, while the hypoglycemic case requires consideration of both in-sulin a...
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The electron transmission properties of a semiconducting wire are investigated via the tight-binding approximation. The wire is modeled as a chain of sp-hybrid orbitals, including overlap effects. The transmission probability is calculated using the tensorial Green function method. An impurity in th...
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The introduction of non-orthogonal atomic orbitals, into the tight-binding approximation, gives rise to the existence of overlap terms in electronic band-structure calculations. In contrast to the zero-overlap situation, it is helpful to employ a tensorial Green-function approach to access the surfa...
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A tight-binding investigation is performed of the electronic structure of a semi-infinite monatomic chain, whose atomic orbitals are assumed to be non-orthogonal, so that the effects of overlap can be taken into account. In addition to markedly modifying the bulk band-edges, the presence of overlap ...
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The usual tight-binding (TB) approximation, employed in electronic structure calculations, is extended to include the more-distant neighbor sites than the first. In doing so, a simple power law is adopted to describe the bond and overlap contributions, which enables the energy dispersion relation to...
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The electron transmission properties of a molecular wire, containing a single impurity, are investigated in the context of the tight-binding approximation. The inclusion of overlap gives rise to nonorthogonal orbitals, whose treatment requires a tensorial formalism to obtain the Green function arisi...
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In many scientific disciplines, measurements are taken from films that have been exposed to energetic sources. Examples include radiographs where the source is an X-ray tube, autoradiography where the source is a radioactive isotope and electrophoresis gels where the source is an enhanced chemilumin...
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This paper studies the effect of varying substrate temperatures on the resonant charge-transfer process between a scattered particle and a solid surface. Two possible mechanisms for an effect are considered: (1) coupling of the transferring electron to the thermal motion of the target atom on the su...
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The recursive Green function (RGF) method is used to obtain the surface and adatom RGFs for an electrified substate. The electrochemisorption (ECS) process is described, by invoking the Anderson-Newns (AN) model, whereby a self-consistent treatment of the ECS energy and charge transfer is provided. ...
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McDowell's 1985 electronic bath theory of charge transfer is used to investigate the effect of varying surface temperature on the process of ion scattering from a solid surface. As a specific example, the system of Na+ scattered from W is modeled. The neutralization probability is found to have a si...
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A methodology of transmission through two-dimensional tight-binding lattices is presented. The theory is formulated in terms of matrix algebra and the relationships between the matrices are examined in detail. The features specific to tight-binding systems are contrasted to those for more general tr...
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We consider the problem of comparing the suitability of various magnetic lattices for the spin polarization of neutrons. To do this, we use a discrete model to construct measures of transmission through one-dimensional lattices. We examine the model for non-periodic lattices that are generated from ...
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Many previous studies of obese rodents documented biochemical changes in pancreatic islets that contribute to hyperinsulinemia in vivo. Those studies used heterogeneous populations of islets, although the size of islets from obese rats ranges from 500 microm. Here, functional and morphological chang...
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A brief overview is given of the theory of surface-ion neutralization (SIN) by highlighting studies from the pioneering days to the present time. Emphasis is placed on the 1-electron time-dependent Newns-Anderson (TDNA) model, which has played such a key role in studying resonance charge transfer. R...
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Recursive procedures are found for calculating the kth-order entropy of non-periodic sequences. These entropies are used as measures of disorder of the sequences and we treat: the Fibonacci sequence and generalizations; the Thue-Morse sequence together with generalizations and the period-doubling se...
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An empirical tight-binding (ETB) approach combined with a Green's-function (GF) method has been employed to investigate the electronic structure of the Si(111) and arsenic-passivated Si(111) surfaces. An accurate silicon band structure has first been developed keeping up to second-nearest-neigh...
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We present a theoretical model for studying the effects of an electromagnetic (laser) field on the process of neutralization of an ion during scattering by a surface. The model is part of a many-electron theory within the framework of a time-dependent version of the Anderson-Newns model. Where we sp...
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We develop a theoretical framework for investigating charge-transfer processes occurring during the scattering of an ion from a solid surface, in the presence of a pulsed laser field. The theory is based upon the many-electron formalism, previously used by our group, to investigate charge transfer b...