Binding force described

Chem., 20, 1177 (1999). BLEEP-Potential of Mean Force Describing Protein-Ligand Interactions. II. Calculation of Binding Energies and Comparison with Experimental Data. 

Surfaces act like lattice vacancies they change the binding forces and the distances and lead to a condition which can be called stress if one wants to describe it macroscopically. This condition within a surface film or within the skin of a solid is the result of an asymmetry in the electron density distribution. Hence, everything which affects the symmetry of a surface, even physically adsorbed atoms of the inert gases, must be expected to affect the properties of the solid. 

The property describing the binding force of an electron to a nucleus is the ionization potential, IP, which is the energy required to remove an electron from an atom or molecule in the gas phase. The electron affinity, EA, is the energy released when an electron combines with an atom or molecule. On the basis of these definitions, electron transfer is feasible when the electron affinity exceeds the ionization potential ... 

J. B. O. Mitchell, R. A. Laskowski, A. Alex, M. J. Forster and J. M. Thornton, BLEEP-Potential of mean force describing protein-ligand interactions II. Calculation of binding energies and comparison with experimental data.. Journal of Computational Chemistry, 1999, 20, 1177-1185. 

More work is required in order to clarify the molecular structure of these fascinating molecular assemblies which seem to be on the borderline between fluid and solid micellar rods. Their formation develops through a certain type of precipitation, also typical for solid micellar fibres. However, the binding forces between the head group molecules (tetraalkylammonium and phenol) are weak, meaning that the fibres are not as stiff and uniform as the crystalline fibres described later. Aqueous suspensions of the described fibres dissolve massive amounts of small hydrocarbon molecules, e.g. 20 mol % of hexane, but the dissolving of hydrophobic porphyrins in them has not yet been achieved. 

This identification of the chemical and the physical bond at once led to the association with the chemist s ionic and covalent bonds of two other types of binding force not previously regarded as chemical in nature at all, namely, the metallic bond responsible for the cohesion of a metal, and the very much weaker van der Waals or residual bond responsible for the crystallization of the inert gases at very low temperatures. These metallic and van der Waals forces, however, did not lend themselves as readily as did the ionic and covalent to any simple explanation in terms of the Bohr theory, and it is only in recent years that the development of quantum mechanics has enabled a qualitative and even quantitative description of these bonds to be given. At the same time quantum theory has furnished a more exact description of the properties of the ionic and covalent bonds, which were previously so successfully described qualitatively in terms of older ideas, so that it is now possible to give a satisfactory theoretical explanation of many of the physical and chemical properties of simple structures. 

It is possible to infer these structures, that of lowest energy and others of higher energy as well, from simple models for some kinds of clusters. This is particularly so for atomic clusters whose binding forces are well represented by pairwise interactions such as the Lennard-Jones potentials that approximate van der Waals interactions, or the Born-Mayer interactions that describe the forces between the ions in alkali halide clusters. Many molecular clusters also behave much like their simple models, models... 

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