What is the Lennard-Jones potential?
The Lennard-Jones Potential (or the L-J potential, 6-12 potential, or 12-6 potential) is a simple model that approximates the interaction between two particles, a pair of neutral atoms or molecules, which repulse at short distances and attract at large. Thus, it is based on their distance of separation. The equation takes into account the difference between attractive forces and repulsive forces.
If two rubber balls are separated by a large distance they are not interacting each other. When we bring both balls closer together they begin interacting. The balls can continuously be brought closer together till they are touching. When they touch, it becomes increasingly difficult to further decrease the distance between the two balls because In order to bring them closer, we would need to add increasing amounts of energy because eventually, when the balls begin to invade each other’s space, they repel - the force of repulsion is far greater than the force of attraction.
The L-J potential is a relatively good approximation and due to its simplicity is often used to describe the properties of gases.