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van der Waals Force, Dipole-Dipole Interaction

All atoms and molecules -- even inert-gas such as those of helium and argon -- exhibit weak, short-range attractions for one another due to van der Waals forces. These forces are responsible for the condensation of gases into liquids and the freezing
Van der Waals Interaction Van der Waals, Nonpolar of liquids into solids. Such familiar aspects of the behavior of matter in bulk as friction, surface tension, viscosity, adhesion, cohesion, and so on also arise from van der Waals forces. The interaction is between dipole-dipole. It can be the interaction between a permanent and an induced dipole as shown in Figure 12-17 or between a time average dipole (due to fluctuations of charge) and an induced dipole as shown in Figure 12-18. The van der Waals interaction is about 10 times weaker than hydrogen

Figure 12-17 van der Waals Interaction [view large image]

Figure 12-18 van der Waals, Nonpolar
[view large image]

bond. The stronger hydrogen bond can be considered as interaction between permanent dipoles.

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