They are responsible for the term inversely proportional to the sixth power of distance in the Lennard-Jones potential.  
The mathematical expression for them is sometimes splined together with a Morse potential for better agreement with experiment.  One model for these interactions is a three-body potential which includes the product of three cosines of angles, and is named for Axilrod and Teller.  Another model of these interactions was created by H.C. Hamaker.   One type of these interactions is named for (*) Keesom, while another is named after Debye.  They are responsible for the term inversely proportional to the sixth power of distance in the Lennard-Jones potential.  FTP, identify this class of intermolecular forces which includes London dispersion forces, and is named for a Dutchman.
The mathematical expression for them is sometimes splined together with a Morse potential for better agreement with experiment.  
{van der Waals} forces [Accept {London} dispersion forces before (*). DO NOT accept afterwards. Prompt on "intermolecular" forces.]