Forces also van der Waals

The albumin molecule has different binding sites for anionic and cationic ligands, but van der Waals forces also contribute (p. 58). The extent of binding correlates with drug hydrophobicity (repulsion of drug by water). 

In general, noble gases interact with other elements (and themselves) chiefly through van der Waals forces, also known as dispersion forces, which arise in elec-... 

Van Der Waals forces Also called dispersion forces, these occur when small, temporary dipoles are formed because of the random motion of electrons. 

The three intermolecular forces are dipolar attractions, van der Waals forces (also called London forces), and hydrogen bonding. The effects of dipoles (Section 13.5) are considered first, followed by discussions of van der Waals forces and hydrogen bonding. 

The main feature of the model is that it considers the a-framework and the 7t-electrons separately. It concludes that apparently net favourable 7t-7i interactions are not due, in fact, to attractive electronic interactions between the two 7i-systems, but rather occur when the attractive interactions between the 7t-electrons and the o-framework (namely, 7i-a attractions) outweigh the unfavourable k-k repulsions that are present. Although van der Waals forces also contribute to the interaction energy, it is the electrostatic 7i-a interactions that dictate the preferred geometry to be adopted. 

There is reason to believe that hydrogen bonding takes place between primary amino and acetyl groups and that Van der Waals forces also contribute to the retention of the dye... 

The reason for this behavior involves the nature of intermolecular forces of attraction. Although we will not be focusing on the nature of these forces, it is helpful to know what they are called. The force of attraction between polar molecules is called dipole-dipole interaction between nonpolar molecules, forces of attraction are called van der Waals forces (also called London or dispersion forces). In both cases, these attractive forces can occur between molecules of the same compound or different compounds. Consult your lecture textbook for more information on these forces. 

Van der Waals force Also called intermolecular forces, secondary valence forces, dispersion force, London dispersion force, or van der Waals attraction. It is an attractive force between two atoms or non-polar molecules, which arise because a fluctuating dipole moment in one molecule induces a dipole moment in the other, and the two dipole moments then interact. They are somewhat weaker than hydrogen bonds and far weaker than inter-atomic valences. Information regarding their numerical values is mostly semi-empirical, derived with the aid of theory from an analysis of physical and chemical data. 

London Dispersion Forces (London Forces) n [fr. Fritz London. (1930) Identifies weak intermolecular forces based on transient dipole interactions. One of van der Waals forces, also called dispersion forces, but distinct from dipole-dipole forces. These forces arise fi om momentary fluctuations in the electron charge cloud density in a atom or molecule. Changes in symmetry of the electron cloud that cause a momentary dipole moment and attractive/repulsive charges. The larger a molecule is and the more electrons it has, the more polarizable it will be, and thus the larger the London forces can be. Molecular shape and other factors are also important. (Whitten KW, Davis RE, Davis E, Peck LM, Stanley GG (2003) General chemistry. Brookes/Cole, New York)... 

This resulting force between the two particles is known as the van der Waals force (also called the London dispersion force). Like the metallic and ionic bonds, the force acts along the line between any two particles, so it is best described as a central force. Because there is no charge on the particles, close-packed structures are favored in van der Waals solids. Note that the attractive (negative) part of the potential goes as (or which is the correction for the molecular interaction in the equation of state for a van der Waals gas). 

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