Bonding theories chain

The distances found between platinum centers in these molecules have been correlated with the resonating valence bond theory of metals introduced by Pauling. The experimentally characterized partially oxidized one-dimensional platinum complexes fit a correlation of bond number vs. metal-metal distances, and evidence is presented that Pt—Pt bond formation in the one-dimensional chains is resonance stabilized to produce equivalent Pt—Pt distances.297 The band structure of the Pt(CN)2- chain has also been studied by the extended Huckel method. From the band structure and the density of states it is possible to derive an expression for the total energy per unit cell as a function of partial oxidation of the polymer. The equilibrium Pt-Pt separation estimated from this calculation decreases to less than 3 A for a loss of 0.3 electrons per platinum.298... 

Rivelino R, Chaudhuri P, Canuto S (2003) Quantifying multiple-body interaction terms in H-bonded HCN chains with many-body perturbation/coupled-cluster theories. J Chem Phys 118 10593-10601... 

As new complex ions were synthesized, several bonding theories were postulated and rejected. The two most convincing theories, the Blomstrand-Jorgensen chain theory and coordination theory proposed by Alfred Werner, were debated extensively (a subject taken up in detail in Chapter 2) and it was coordination theory that eventually proved to be correct, winning Wemer the Nobel Prize in 1913. 

The network is deformed at a constant temperature T and a rate of elongation e. During deformation, the bonds between chains are allowed to break according to the Eyring kinetic theory of fracture (7), ie, at a rate... 

Many refinements can be introduced into the theory. First of all, it would be worthwhile to pay further attention to the structure of water around the polar groups. Perhaps, when the hydrophobic bond (and the role of water in it) is better understood, it may be possible to modify the hydrogen-bonding theory to take the water into account. Second, the helices need not be held rigidly with respect to each other, i.e., side-chain hydrogen bond rupture may lead to increased mobility of the backbone chains, allowing the R groups to move quite a distance away from each other. Third,... 

All the studies conducted on fracture of bulk polymers are certainly relevant to the adherence of polymers, the mechanisms of losses at a crack tip being the same viscoelastic losses due to moving stresses, work to extract chains or fibrils, and viscous drag in the presence of a liquid. It is probable that the various theories of adhesion, namely, theory of wetting, theory of the rheological factor, theory of the chemical bond, theory of the weak boundary layer, and theory of interdiffusion, are all valid, each corresponding to an emphasis on a dominant mechanism. 

Thus, the stated above results demonstrated, that fractal analysis application for polymers fracture process description allowed to give more general fracture concept, than a dilation one. Let us note, that the dilaton model equations are still applicable in this more general case, at any rate formally. The fractal concept of polymers fracture includes dilaton theory as an individual case for nonfractal (Euclidean) parts of chains between topological fixation points, characterized by the excited states delocalization. The offered concept allows to revise the main factors role in nonoriented polymers fracture process. Local anharmonicity ofintraand intermolecular bonds, local mechanical overloads on bonds and chains molecular mobility are such factors in the first place [9, 10]. 

Soos, Z. G. Ramasesha, S. Galvao, D. S. Band to correlated crossover in alternating Hubbard and Pariser Parr Pople chains nature of the lowest singlet excitation of conjugated polymers, Phys. Rev. Lett. 1985, 71, 1609-1612 Soos, Z. G. Ramasesha, S. Valence bond theory of linear Hubbard and Pariser-Parr-Pople models, Phys. Rev. 1984, B29, 5410-5422. 

A kinetic theory of fracture intends to interrelate the motion and response of molecules to the ultimate properties of a stressed sample. A kinetic theory, therefore, entails a molecular description of the deformation of the microscopically heterogeneous and anisotropic aggregates of chains to such an extent that critical deformation processes can be identified. The macroscopic deformation of any aggregate potentially involves the deformation, displacement, and/or reorientation of so different substructural elements as bond vectors, chain segments or crystal lamellae. 

A careful study of the molecular structure by microwave methods provides numerous interesting structural features. For example, it is apparent from Table III that the CF bond in FCN is shorter than in FCP. Many observations of this nature have been made and often correlated with simple bonding theory. A different effect may be illustrated by the —C"N chain in methylene cyanide, CH2(CN)2, and sulfur dicyanide, S(CN)2, which is not linear, but rather is bent slightly by about 3° and 5°, respectively. Such effects are not confined to the presence of a cyano group. Similar... 

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