Stationary facets

The theory of atoms in molecules192 recovers all the fundamental concepts of chemistry, of atoms and functional groups with characteristic properties, of bonds, of molecular structure and structural stability, and of electron pairs and their role in molecular geometry and reactivity. The atomic principle of stationary action extends the predictions of quantum mechanics to the atomic constituents of all matter, the proper open systems of quantum mechanics. All facets of the theory are predictive and, as a consequence, the theory can be employed in many fields of research at the atomic level, from the design and synthesis of new drugs and catalysts, to the understanding and prediction of the properties of alloys. 

Figure 1 shows the variation of the stationary rate of C02 formation with CO pressure at fixed temperature and 02 pressure for both a well-annealed, flat Pt(l 10) surface (solid line) and the same surface exhibiting periodic arrays of monoatomic steps forming facets (broken line) (23). At low CO pressures, the surface is largely covered by Oad, and the rate increases linearly with pco. Nearly every CO molecule striking the surface... 

From the microscopic point of view, again the CO-induced 1 x 2- 1 x 1 structural transformation of the Pt(l 10) surface (as also underlying the mechanism of temporal oscillations) is of crucial importance for the development of facets, as becomes evident from the fact that this effect is restricted to conditions of high stationary CO coverages. Simply speaking, CO adsorption lifts the 1 x 2 reconstruction and simultaneously creates... 

Fig. 25. CO/O, reaction on Pt(llO) pco = 2.3 x 10 5 torr, T = 470 K. At the point marked by an arrow, p,h was changed from 1.5 to 2.0 x 10 4 torr. The stationary reaclion rate starts to increase slowly due to faceting until oscillatory conditions are reached. (From Ref. 24.)...

This examination also illustrates another facet of chain reactions Granted quasi-stationary conditions and long chains, the concentrations of the chain carriers are coupled, in reactions like 9.5 through the requirement that the rates of the two propagation steps must be equal. Therefore, only one of the two chain carriers can be in dissociation equilibrium with its source, the other gets boosted by the propagation cycle to a higher than thermal concentration. 

Figure 5.35. Principle of the lamellar grating interferometer. Radiation reflected from the movable facets travels a distance of Idicos a farther than the radiation reflected from the stationary (shaded) facets.

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