More general potentials

With only repulsive interactions it is not possible to study the usual solid/liquid/gas phases which correspond to most materials we know. It is possible however to make a more general interaction potential that can be simulated with event driven methods. For instance:

Find the collisions rules for the square-well system and write code to follow the dynamics. Somewhat trickly to get right... This has all the usual 3 phases that we are used to in materials, solid, liquid and gas.