Energetics of Adsorbed Dimers VIA Self-Consistent Scattering Theory

1987 ◽  
Vol 111 ◽  
Author(s):  
Peter J. Feibelman

AbstractA new approach to the surface electronic structure problem, based on a self-consistent scattering theory of point defects, permits 1st-principles calculations for an isolated cluster of adatoms and defects on an otherwise perfect infinite crystalline surface. A first numerical application of the method explains important observations concerning the interaction and diffusion of adatom dimers on Field Ion Microscope tips. Further studies will shed light on questions such as: What impurity species migrate to what kind of surface defects? What is the contribution of substrate atom positional relaxation to adsorption and diffusion barrier energies?

1980 ◽  
Vol 21 (6) ◽  
pp. 2055-2059 ◽  
Author(s):  
F. J. Arlinghaus ◽  
J. G. Gay ◽  
J. R. Smith

The only existing theory of atmospheric turbulence which is capable of giving a quantitative approach to the complex problems of diffusion in the lower atmosphere is the classical theory in which it is generally assumed that the effect of eddies in the atmosphere is completely analogous to that of molecules in a gas apart from a difference of scale. This assumption, which later evidence has shown to be incorrect, is not essential to the theory, and in the present paper is replaced by the assumption that the mixing length of an eddy increases with both height above and nature of the earth’s surface . With this assumption a self-consistent treatment of diffusion is developed which is able to account quantitatively for such meteorological phenomena as the distribution of water vapour over land and sea (including evaporation from the oceans) and the diffusion of smoke near the ground. The treatment is mainly confined to diffusion in an adiabatic atmosphere.


1991 ◽  
Vol 05 (03) ◽  
pp. 427-459 ◽  
Author(s):  
EDWARD H. CONRAD

The study of defect formation at metal surfaces is a fundamental problem in surface physics. An understanding of defect formation is pertinent to growth and diffusion mechanisms. In addition, surface roughening, faceting, and surface melting are all defect mediated phase transitions involving the formation of different topological defects. While the importance of defects at surfaces is well recognized, the study of surface defects has been hampered by the lack of sufficiently accurate experimental techniques. In fact, it is only in the past 6 years that experiments on the thermal generation of defects on metal surfaces have been performed. This review attempts to outline both the theoretical and experimental work on surface defect formation on metal systems.


1998 ◽  
Vol 527 ◽  
Author(s):  
Zokirkhon M. Khakimov

ABSTRACTThis paper presents the self-consistent tight-binding method of new generation which, unlike other tight-binding methods, allows one to calculate structural energies of multiatomic systems (molecules, clusters, defects in solids) and their spectroscopic energies in the framework of the same computational scheme and with comparable accuracy. Reliability of the method is illustrated considering defect state problems in crystalline and amorphous silicon (electron-enhanced-atomic diffusion, metastable defect creation, defects with effective-negative correlation energies, etc.) and comparing obtained results with ab initio calculations and experimental data.


1998 ◽  
Vol 532 ◽  
Author(s):  
Zokirkhon M. Khakimov

ABSTRACTThis paper presents the self-consistent tight-binding method of new generation which, unlike other tight-binding methods, allows one to calculate structural energies of multiatomic systems (molecules, clusters, defects in solids) and their spectroscopic energies in the framework of the same computational scheme and with comparable accuracy. Reliability of the method is illustrated considering defect state problems in crystalline and amorphous silicon (electronenhanced- atomic diffusion, metastable defect creation, defects with effective-negative correlation energies, etc.) and comparing obtained results with ab initio calculations and experimental data.


2004 ◽  
Vol 11 (04n05) ◽  
pp. 457-461 ◽  
Author(s):  
P. JUNELL ◽  
M. AHONEN ◽  
M. HIRSIMÄKI ◽  
M. VALDEN

Translational energy ( E T ) dependence of oxygen ( O 2) adsorption on clean and modified Cu {100} has been studied by molecular beam surface scattering (MBSS) experiments. The role of surface defects on the adsorption dynamics has been investigated by blocking the defects with Ag and oxygen atoms, and by increasing the defect density with Ar +-ion bombardment. At low E T the adsorption of O 2 is shown to be indirect and facilitated either by a dynamical steering mechanism or a precursor state. At high E T the defects have only marginal effect on the adsorption. Additionally, the modification of the surface electronic structure by preadsorbed oxygen is shown to have a pronounced effect on the adsorption dynamics, whereas the electronic structure modification by preadsorbed Ag is shown to be relatively inefficient in changing the reactivity of Cu {100} towards O 2 adsorption.


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