The interaction of two systems, such as atoms or molecules, by their dipole moments. The energy of dipole-dipole interaction depends on the relative orientation and the strength of the dipoles and how far apart they are. A water molecule has a permanent dipole moment, thus causing a dipole-dipole interaction if two water molecules are near each other. Although isolated atoms do not have permanent dipole moments, a dipole moment can be induced by the presence of another atom near it, thus leading to induced dipole-dipole interactions. Dipole-dipole interactions are responsible for van der Waals' forces and surface tension in liquids.
Subjects: Chemistry — Physics.