Keesom-type interaction energy

D18.4 There are three van der Waals type interactions that depend upon distance as l/r6 they are the Keesom interaction between rotating permanent dipoles, the permanent-dipole-induced-dipole-interaction, and the induced-dipole-induced-dipole, or London dispersion, interaction. In each case, we can visualize the distance dependence of the potential energy as arising from the Mr dependence of the field (and hence the magnitude of the induced dipole) and the Mr3 dependence of the potential energy of interaction of the dipoles (either permanent or induced). 

In linear polymers, cohesion results from weak (compared with covalent bonds) intermolecular attractive forces (Van der Waals) of various types London, Debye, Keesom, and hydrogen bonding. In a first approach, they can be considered undistinguishable, and one can define cohesive energy as the whole energy of intermolecular interactions. For small molecules, cohesive energy is easy to determine from calorimetric measurements since... 

In the early 1960s, Fowkes [88,89] introduced the concept of the surface free energy of a solid. The surface free energy is expressed by the sum two components a dispersive component, attributable to London attraction, and a specific (or polar) component, y p, owing to all other types of interactions (Debye, Keesom, hydrogen bonding, and other polar effects, as similarly described before in Sec. II. C... 

As is well known, atoms or molecules always attract each other at short distances of separation. The attractive forces are of three different types dipole-dipole interaction (Keesom) dipole-induced dipole interaction (Debye) and London dispersion force. Of these forces, the London dispersion is the most important as it occurs for polar and nonpolar molecules. It arises from fluctuations in the electron density distribution, and at small distances of separation r in vacuum, the attractive energy between two atoms or molecules is given by,... 

Intermolecular forces between molecules result from interactions between their corresponding electron orbitals. The principal non-bonding interactions result from induced dipole-induced dipole (London), dipole-induced dipole (Debye) and dipole-dipole (Keesom) interactions. The intermolecular potential energy function, U, for each of these three types of interactions is of the same form. Here, r is the separation distance between bodies. 

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