Hertzian sphere model
The Hertzian sphere model is given by [1] (Eq. 1):
where is the intermolecular pair potential, is the distance between site 1 and site 2. represents a length scale and an energy. In the limit this potential becomes the hard sphere model. For example, for Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle \epsilon =10} the potential looks like