The Chemistry of Atoms

Summarizing the results obtained for neutral atoms and positive and negative ions we can conclude that Strutinsky s shell-correction procedure in the EKS-DFT scheme is a helpful tool for investigating such important properties for the chemistry of atomic systems as the ionization potential,... 

The chemistry of atoms is dominated by the outermost atomic orbitals, which are, so to speak, their atomic frontier orbitals. This is not true, however, of transition metals, where the (n — l)d orbitals must also be taken into account because they lie very close in energy to the ns and np orbitals. The same kind of problem occurs in molecules. The subjacent or superjacent MOs may determine the outcome of a reaction if they lie close in energy to the frontier orbitals (p. 113) or if they are nonbonding orbitals (Exercise 3, p. 59). 

Because so much of the chemistry of atoms and molecules is related to their structures, the study of descriptive chemistry begins with a consideration of these topics. The reasons for this are simple and straightforward. For example, many of the chemical characteristics of nitrogen are attributable to the structure of the N2 molecule, N = N . The triple bond in the N2 molecule is very strong, and that bond strength is responsible for many chemical properties of nitrogen (such as it being a relatively unreactive gas). Likewise, to understand the basis for the enormous difference in the chemical behavior of SF4 and SF6 it is necessary to understand the difference between the structures of these molecules, which can be shown as... 

If the issue of n-complex formation with PMDA-ODA polyimide seems confused, the results of model compound studies have, in places, exacerbated the problem. Several research groups have turned to reactions of formally zerovalent chromium to model the chemistry of PMDA-ODA/Cr (58e, 60. 62) The studies assume that the chemistry of atomic Cr and of certain chromium carbonyl complexes is coextensive. Since atomic chromium has not been available as a benchtop reagent, popular sources of formally zerovalent chromium, disguised as Cr(CO)6 and (CH3CN)3Cr(CO)3, have been used. These compounds readily form (arene)Cr(CO)3 complexes (71). 

The chemistry of atomic nitrogen, N(4S), in aqueous solution has been investigated by bubbling a stream of active nitrogen into water (83). It was found that N(4S) reacts with alcohols, and the reaction was proposed to proceed by insertion into a C-H bond. The water was found to be rather unreactive. Further work in this area would be facilitated by an in situ source of N(4S). 

The orbital concept is the basis for most qualitative discussions of the chemistry of atoms and molecules. The use of orbitals, however, is an approximation. To reach the true wave function, we must go beyond a Slater determinant of spin-orbitals. Two review articles on atomic orbitals are R. S. Berry,/. Chem. Educ., 43,283 (1966) and I. Cohen andT. Bustard,/. Chem. Edua,43,187 (1966). 

The orbital concept is the basis for most qualitative discussions of the chemistry of atoms and molecules. The use of orbitals, however, is an approximation. To reach the true wave function, we must go beyond a Slater determinant of spin-orbitals. 

Atomic Carbon.—Skell and Plonka have extended their studies of the chemistry of atomic carbon, which they generate in a low-intensity carbon arc. The mechanism of the conversion of carbon-hydrogen bonds to carbon-methyl bonds has been investigated thoroughly the detection of triplet carbenes as intermediates infers that the inserting carbon atoms are in the state. 

Similarly detailed information on the chemistry of atoms at. surface sites and on the relationships of such sites to surface reactivity may be obtained for oxide, silicate, aluminosilicate and other minerals using XPS in a.s.sociation with EXAFS and adsorption studies. The reviews by Bancroft and Hyland [481. and Brown et al. [16], provide many examples of the types of information obtainable for these surfaces. 

Unfortunately this interpretation does not leave room for a discussion of the chemistry of atoms or in other words for the attempt to reduce the periodic table of the elements to quantum mechanics or atomic theory, which is a question that Hettema and Kuipers claim to discuss in their article. The authors continue by saying,... 

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