Atomic oxygen ion

Different methods have been developed for the generation of carbene and diradical negative ions. One of the most commonly used approaches involves the reaction of an organic substrate with atomic oxygen ion, O , to form water by H2 abstraction (Eq. 5.7). "... 

D. G. Hopper, Mechanisms of the Reaction of Positive Atomic Oxygen Ions with Nitrogen, private communication. 

The purpose of calculating Henry s Law constants is usually to determine the parameters of the adsorption potential. This was the approach in Ref. [17], where the Henry s Law constant was calculated for a spherically symmetric model of CH4 molecules in a model microporous (specific surface area ca. 800 m /g) silica gel. The porous structure of this silica was taken to be the interstitial space between spherical particles (diameter ca. 2.7 nm ) arranged in two different ways as an equilibrium system that had the structure of a hard sphere fluid, and as a cluster consisting of spheres in contact. The atomic structure of the silica spheres was also modeled in two ways as a continuous medium (CM) and as an amorphous oxide (AO). The CM model considered each microsphere of silica gel to be a continuous density of oxide ions. The interaction of an adsorbed atom with such a sphere was then calculated by integration over the volume of the sphere. The CM model was also employed in Refs. [36] where an analytic expression for the atom - microsphere potential was obtained. In Ref. [37], the Henry s Law constants for spherically symmetric atoms in the CM model of silica gel were calculated for different temperatures and compared with the experimental data for Ar and CH4. This made it possible to determine the well-depth parameter of the LJ-potential e for the adsorbed atom - oxygen ion. This proved to be 339 K for CH4 and 305 K for Ar [37]. On the other hand, the summation over ions in the more realistic AO model yielded efk = 184A" for the CH4 - oxide ion LJ-potential [17]. Thus, the value of e for the CH4 - oxide ion interaction for a continuous model of the adsorbent is 1.8 times larger than for the atomic model. 

The F-region begins above 130 km and is sometimes subdivided into two layers, Fi and F2. It is primarily produced by ionization of atomic oxygen and molecular nitrogen by extreme ultraviolet radiation (9-91 nm). The atomic oxygen ion, 0+, dominates. The electron density attains its maximum value of about 106cm-3 in this layer. The F-region plays an important role in the transmission of certain radio waves, which... 

In reactions with molecular targets, dissociative processes are often observed. This is the case of the Xe++( D2) reaction with oxygen, where both molecular and atomic oxygen ions are formed as products (Adams et al., 1979) ... 

A significant contribution to NO synthesis in non-thermal air plasma can be provided by ion-molecular reactions, especially those involving positive atomic oxygen ions ... 

A. L. Schmeltekopf, F. C. Fehsenfeld, G. I. Gilman, and E. E. Ferguson, Reaction of atomic oxygen ions with vibrationally excited nitrogen molecules. Planetary Space Sci. 15, 401-406(1967). 

In many crystals there is sufficient overlap of atomic orbitals of adjacent atoms so that each group of a given quantum state can be treated as a crystal orbital or band. Such crystals will be electrically conducting if they have a partly filled band but if the bands are all either full or empty, the conductivity will be small. Metal oxides constitute an example of this type of crystal if exactly stoichiometric, all bands are either full or empty, and there is little electrical conductivity. If, however, some excess metal is present in an oxide, it will furnish electrons to an empty band formed of the 3s or 3p orbitals of the oxygen ions, thus giving electrical conductivity. An example is ZnO, which ordinarily has excess zinc in it. 

The use of larger particles in the cyclotron, for example carbon, nitrogen or oxygen ions, enabled elements of several units of atomic number beyond uranium to be synthesised. Einsteinium and fermium were obtained by this method and separated by ion-exchange. and indeed first identified by the appearance of their concentration peaks on the elution graph at the places expected for atomic numbers 99 and 100. The concentrations available when this was done were measured not in gcm but in atoms cm. The same elements became available in greater quantity when the first hydrogen bomb was exploded, when they were found in the fission products. Element 101, mendelevium, was made by a-particle bombardment of einsteinium, and nobelium (102) by fusion of curium and the carbon-13 isotope. 

It is concluded [634] that, so far, rate measurements have not been particularly successful in the elucidation of mechanisms of oxide dissociations and that the resolution of apparent outstanding difficulties requires further work. There is evidence that reactions yielding molecular oxygen only involve initial interaction of ions within the lattice of the reactant and kinetic indications are that such reactions are not readily reversed. For those reactions in which the products contain at least some atomic oxygen, magnitudes of E, estimated from the somewhat limited quantity of data available, are generally smaller than the dissociation enthalpies. Decompositions of these oxides are not, therefore, single-step processes and the mechanisms are probably more complicated than has sometimes been supposed. 

The recombination should be governed by the same selection rules as spectroscopic transitions. Let us consider the recombination of an oxygen ion 2s2 2p3 4S°. When one p electron is added to the 4S ion we expect to obtain one of the states 5P and 3P. However, if the 2s2 2p4 state of the atom is obtained, it can only exist in the states 3P, lD, or lS. Thus the recombination can only give 2s2 2p4 3P. Sometimes the selection rules are not strictly valid. In this case, however, no transitions 2s2 2p3 4S° nx - 2s2 2p4 XD or lS have been observed by the spectros-copists (57) which shows that in this case the selection rules are strictly valid. 

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