A local–orbital based ab initio approach to obtain the Green function for large heterogeneous systems is developed. First a Green function formalism is introduced based on exact diagonalization. Then the self energy is constructed from an incremental scheme, rendering the procedure feasible, while at the same time physical insight into different local correlation contributions is obtained. Subs...

Low-energy electronic states in heterosrtuctures formed by ultranarrow layers (single or several monolayers thickness) are studied theoretically. The host material is described within the effective mass approximation and effect of ultranarrow layers is taken into account within the framework of the transfer matrix approach. Using the current conservation requirement and the inversion symmetry o...

The dependence of the transmission coefficient on the deformation, the collective rotation and excitation energy of the compound nucleus emitting light particles is introduced in the framework of Weißkopf’s evaporation theory. The competition between fission and particle evaporation is treated by a Langevin equation for the fission variable coupled to the emission process. Detailed calculations...

An analysis of free convective MHD visco-elastic fluid flow with heat and mass transfer over a vertical plate moving with a constant velocity in presence of Dufour and Soret effects has been presented. The fluid is considered to be non-Newtonian characterized by Walters liquid (Model B′). The surface temperature is assumed to oscillate with small amplitude about a non-uniform mean temperature. ...

We have developed a generalized Bloch wave approach for the analysis of aperiodic gratings. This method yields both a macroscopic (i.e., reflection or transmission coefficient) as well as a microscopic (i.e., dispersion diagram and microstructure of the propagating internal field) characterization of fiber and waveguide aperiodic gratings.

We use a simple model to determine the frequency-dependent effective elastic coefficients of a three-dimensional phononic crystal, consisting of periodically arranged solid spheres embedded in fluid host, through theoretical calculations of the transmission coefficient and frequency band structure diagrams, using multiple-scattering techniques. Our results are successfully compared to those obt...

Problem statement: A steady two-dimensional free convection and mass transfer flow past a continuously moving semi-infinite flat plate is studied theoretically, by taking into account the viscous dissipation effect. Approach: The governing equations are transformed into a set of simultaneous ordinary differential equation by using suitable similarity transformations. The coupled differential eq...

The thermoelectric transport properties of CaMg2Bi2, EuMg2Bi2, and YbMg2Bi2 were characterized between 2 and 650 K. As synthesized, the polycrystalline samples are found to have lower p-type carrier concentrations than single-crystalline samples of the same empirical formula. These low carrier concentration samples possess the highest mobilities yet reported for materials with the CaAl2Si2 stru...

We discuss the combined effect of Rashba and Dresselhaus spin-orbit interactions in polygonal loops formed by quantum wires, when the electron are injected in a node and collected at the opposite one. The conditions that allow perfect localization zero transmission coefficient are found. Furthermore, we investigate the suppression of the transmission coefficient oscillations that appear, in the...

A basic problem when calculating reaction rates using the reactive flux method is the introduction of a reaction coordinate. In this paper we show that it is advantageous to define a reaction coordinate by means of the unstable normal mode of the saddle point of the potential energy surface. This particular choice is made since it yields a high transmission function. Moreover, the reaction coor...