Electron overlap potential, work

Embedded atom interatomic potentials can be formally derived from DFT [188-194]. This class of interatomic potentials generally works well for bulk metallic systems (i.e., accurately reproduces mechanical and stractural properties), due to its relationship to the band model of electronic structure, which is related to the overlap of local electron densities to form the/ree electron gas of the metallic system. By parameterizing the form of the electron density about an atomic center, one can build a model for the electron overlap in these systems and, hence, the many-body features of alloy systems. The resultant expression for... 

STM is based on the tunneling of electrons between the surface and a very sharp tip [36,49]. As explained in the Appendix, the cloud of electrons at the surface is not entirely confined to the surface atoms but extends into the vacuum (this effect causes the electric dipole layer at the surface that contributes to the work function). When an extremely fine tip (see Fig. 7.18) approaches the surface to within a few angstroms, the electron clouds of the two start to overlap. A small positive potential... 

At first sight it would look as if the definition of surface potential (x) described in Section 6.4.8 would overlap with the definition of the workfunction. Does this mean that both quantities are the same but with opposite signs To answer this question, let us look closer to the trajectory of the electron as defined in the work function (Fig. 6.45). The electron starts in a point deep inside the metal, where all different types of chemical bondings and interactions exist. After breaking all these forces, the electron moves itself free from inside the metal to a point close to the surface. Then, from here it has to cross the barrier of dipoles (see Section 6.3.8) to reach a point just outside the metal. 

The semiconductor nanocrystallites work as electron acceptors from the photoexcited dye molecules, and the electron transfer as sensitization is influenced by electrostatic and chemical interactions between semiconductor surface and adsorbed dye molecules, e.g., correlation between oxidation potential of excited state of the adsorbed dye and potential of the conduction band level of the semiconductor, energetic and geometric overlapping integral between LUMO of dye molecule and the density of state distribution of the conduction band of semiconductor, and geometrical and molecular orbital change of the dye on the... 

Positronium in condensed matter can exist only in the regions of a low electron density, in various kinds of free volume in defects of vacancy type, voids sometimes natural free spaces in a perfect crystal structure are sufficient to accommodate a Ps atom. The pick-off probability depends on overlapping the positronium wavefunction with wavefunctions of the surrounding electrons, thus the size of free volume in which o-Ps is trapped strongly influences its lifetime. The relation between the free volume size and o-Ps lifetime is widely used for determination of the sub-nanovoid distribution in polymers [3]. It is assumed that the Ps atom is trapped in a spherical void of a radius R the void represents a rectangular potential well. The depth of the well is related to the Ps work function, however, in the commonly used model [4] a simplified approach is applied the potential barrier is assumed infinite, but its radius is increased by AR. The value of AR is chosen to reproduce the overlap of the Ps wavefunction with the electron cloud outside R. Thus,... 

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