Analyze the Lennard-Jones potential with this utility. The Lennard-Jones Fluid 2D program shows a system of particles in two dimensions interacting via the Lennard-Jones potential. The program displays the particles in the box as a function of time once the partition dividing the box into three parts are removed. The program is distributed as a ready-to-run (compiled) Java archive. Double-clicking the ejs_stp_LJFluid2D.jar file will run the program if Java is installed on your computer.

The program was created using Ejs (Easy Java Simulations). You can modify this program and see how it is designed if you have Ejs installed by right-clicking within the window and selecting Open Ejs Model from the pop-up menu. Ejs, a part of the Open Source Physics Project, is designed to make it easier to access, modify, and generate computer models.

Algorithm
The algorithm for simulating the evolution of the model can be summarized by the following steps:
The particles are placed at random in the center of the box with the constraint that no two particles can be closer than the length s = 1 in the Lennard-Jones potential. This constraint prevents the initial force between any two particles from being too big, which would lead to the breakdown of the numerical method used to solve the differential equations. The velocity of each particle is assigned at random and then the velocity of the center of mass is set to zero.
The total force on each particle is computed and the positions and velocities are updated according to the Verlet algorithm.

Requirements:
* Java

The license of this software is Freeware, you can free download and free use this graphing software.