[en] In order to better understand the mechanisms responsible for the lowering of the work function that is observed when surface layers containing barium and oxygen are adsorbed on refractory metals such as tungsten, we have initiated a series of full-potential linearized augmented plane wave electronic structure calculations on well-defined model systems representing the Ba--O/W interface. We report here our initial results for a model in which c(2 x 2)= overlayers of upright BaO molecules have been positioned on both sides of a five-layer W(001) film. Three independent self-consistent calculations were performed involving two different Ba--O separations and two different distances between planes of Ba and surface W atoms. We find that the work function of the clean five-layer tungsten slab (4.65 eV) is lowered by ∼1.8--2 eV by the adsorption of the Ba--O surface layer in this geometry, and that this result is relatively insensitive to the Ba--O separation in the overlayer. The most important factor determining the value of the work function seems to be the position of the barium plane above the W substrate. We find evidence of significant bonding between the d-like surface states of the tungsten substrate and both the Ba d and the oxygen 2p adsorbate levels. As a result, multiple dipoles are formed at the interface and the competition between these polarized charge distributions leads to a net lowering of the work function

[en] We review some salient features of the experimental and theoretical data pertaining to hydrogen negative ion generation on minimum-work-function composite surfaces consisting of Cs/transition metal substrates. Cesium or hydrogen ion bombardment of a cesium-activated negatively-biased electrode exposed to a cesium-hydrogen discharge results in the release of hydrogen negative ions. These ions originate through desorbtion of hydrogen particles by incident cesium ions, desorbtion by incident hydrogen ions, and by backscattering of incident hydrogen. Each process is characterized by a specific energy and angular distribution. The calculation of ion formation in the crystal selvage region is discussed for different approximations to the surface potential. An ab initio, all-electron, local density functional model for the composite surface electronics is discussed

[en] Puska et al. and Astaldi et al. have provided experimental evidence for the existence of hydrogen ion band states in adsorption studies of H and D atoms on metallic surfaces. If a certain view of quantum reality is correct, an ion band state (IBS) D⁺ population has wave function overlap and will undergo cold fusion, unlike normal molecules and ionic and covalent solids. Arguments leading to this conclusion and a tabulation of likely IBS reactions are presented. (author)

[en] The effects that limit deuterium-deuterium (D-D) fusion in bound systems, as opposed to those limiting D-D fusion in free space, are the result of quantum-mechanical particle-particle wave function correlation, which may inhibit wave function overlap. Whether or not this occurs at room temperature is determined by system energy minimization, not Gamow theory. A counterintuitive example, known from atomic physics, that demonstrates how this alternative criterion may alter the relevant quantum mechanics is illustrated by the helium atom. At room temperature, near-complete overlap of the two helium electrons takes place when energy is minimized, while Gamow theory predicts negligible overlap. On the other hand, energy minimization does not predict that no nucleus-nucleus overlap ever occurs in any normal molecule. In D⁺ ion band-state matter, D⁺-D⁺ overlap occurs if the distributed charge view of quantum reality is correct, in which case D⁺ band-state matter converts to ⁴He⁺⁺ band-state matter, releasing heat throughout a crystal lattice. This occurs in the limit x → 1 in PdD_x (in agreement with experiments), provided adequate crystalline order is present. Further deuterium loading requires that additional injected deuterium occupy ionic band-like states in which only a small fraction of each additional deuterium atom occupies a lattice unit cell. Then, in each nuclear reaction, again to minimize energy of the entire system, the energy is distributed over many lattice sites, inhibiting production of energetic particles. Theory shows that steady-state power is proportional to the loading current. These points are discussed. An expression for P is derived, and possible cold fusion reactions are summarized. 23 refs., 1 fig

[en] In this paper a theory of solid-state fusion based on the interaction between D⁺ and ⁴He⁺⁺ ion band states within a host lattice is presented. Formation of ion band-state deuterium is thermodynamically favored when lattice strain energy is greater than the incremental chemical potential of the band state. The key fusion step is a coalescence fluctuation that converts a two-fold occupation state of electrostatic zero-point-motion size into a state of nuclear dimensions. Rates are calculated using the Fermi Golden Rule. Fusion energy is shared between band-state members and subsequently transferred to the lattice

[en] In order to understand better the mechanisms responsible for the lowering of the work function that is observed when surface layers containing barium and oxygen are adsorbed on refractory metals such as tungsten, we have initiated a series of full-potential linearized augmented-plane-wave (FLAPW) electronic-structure calculations on well-defined model systems representing the Ba OE W interface. We report here our initial results for models in which c(2x2) monolayers of barium and oxygen have been positioned on both sides of a five-layer W(001) film, with the adsorbate atoms being placed above the fourfold-hollow sites of the tungsten surface. Two different adsorbate configurations have been investigated: ''tilted,'' where the adsorbed monolayers have been arranged so that the barium and oxygen atoms each cover a different fourfold-hollow site in the c(2x2) unit cell, and ''upright,'' where the overlayers are aligned vertically so that both adsorbates lie above the same site. We have minimized the total energy of the system to determine the optimal adsorbate positions within this set of configurations. We find that the calculated work function of the clean five-layer tungsten slab (4.65 eV) is lowered by approximately 2 eV by the adsorption of the barium and oxygen surface layers in either configuration, but the tilted structure has a significantly lower energy than does the upright. In addition, the position of the oxygen 2s state, which is very sensitive to the adsorbate geometry, strongly favors the tilted model. In both cases we find evidence of significant bonding between the d-like surface states of the tungsten substrate and both the Ba d and the oxygen 2p adsorbate levels. As a result, multiple dipoles are formed at the interface, and the competition between these polarized charge distributions leads to a net lowering of the work function

[en] A new nesting technique has been developed for computing solutions of the steady-state form of the wave action equation. The technique is especially useful for investigating the effects of resolution on the accuracy and stability of the computation. This has importance in the problem of determining ocean wave spectra under the influence of ambient wind fields and current distributions. The technique enables extremely high resolution computations to be performed with minimal computer storage requirements. It is especially useful for applications in modelling radar imagery of the ocean surface. Investigations of the convergence, stability, and accuracy of the procedure are made possible by introducing a fixed grid point location which is common to all the nested grids. In order to display the method, we apply it to a particular model of an oceanographic current rip feature that was recently observed during the first High Resolution Remote Sensing Experiment. Limitations of the method are also discussed. 14 refs., 7 figs., 1 tab

[en] Some salient features of the experimental and theoretical data pertaining to hydrogen negative ion generation on minimum-work-function composite surfaces consisting of Cs/transition metal substrates are reviewed. Cesium or hydrogen ion bombardment of a cesium-activated negatively-biased electrode exposed to a cesium-hydrogen discharge results in the release of hydrogen negative ions. These ions originate through desorption of hydrogen particles by incident cesium ions, desorption by incident hydrogen ions, and by backscattering of incident hydrogen. Each process is characterized by a specific energy and angular distribution. The calculation of ion formation in the crystal selvage region is discussed for different approximations to the surface potential. Results of ab initio, all-electron, local density function calculations for the composite surface electronics of Cs on W(001) and Mo(001) are presented and discussed

[en] We review some salient features of the experimental and theoretical data pertaining to hydrogen negative ion generation on minimum work function composite surfaces consisting of Cs/transition metal substrates. Cesium or hydrogen ion bombardment of a cesium-activated negatively biased electrode exposed to a cesium--hydrogen discharge results in the release of hydrogen negative ions. These ions originate through desorption of hydrogen particles by incident cesium ions, desorption by incident hydrogen ions, and by backscattering of incident hydrogen. Each process is characterized by a specific energy and angular distribution. The calculation of ion formation in the crystal selvage region is discussed for different approximations to the surface potential. An ab initio, all-electron, local density functional model for the composite surface electronics is discussed

[en] We have studied the electronic structure of hydrogen in and on palladium using non-self-consistent layer Korringa-Kohn-Rostoker calculations. These included Pd and H monolayers, three-layer Pd films with monolayers of hydrogen outside and inside, and a p(2 x 2) overlayer. We find that the hydrogen-induced state is practically the same for the monolayers inside and outside but for the (1/4) monolayer outside it is much narrower and closer to the bulk Pd states. These results are compared with existing angle-resolved photoemission data for H on Pd