Fig. 3. Van der Waals London forces. ( A ) Electron clouds in two nonpolar groups ( e.g. , aromatic rings, methyl groups, anesthetic gases) induce instantaneous mutual dipoles which then attract each other, forming a coupled dipole pair. ( B ) The instantaneous electron cloud dipoles (London forces) oscillate. ( C ) Schematic protein oscillates between two conformational states A and B, governed by London force dipoles in nonpolar, hydrophobic pockets. For simplicity, only one nonpolar group is shown in the hydrophobic pocket.