Radial Distribution Function in a Lennard-Jones Fluid

This simulator integrates the equations of motion for 125 Lennard-Jones particles in a periodic 3D box — the same reduced-unit model used to benchmark real molecular-dynamics codes — and builds the radial distribution function g(r) live from the running pairwise-distance histogram. g(r) is the structural fingerprint of a substance: it is directly measurable in the lab from X-ray or neutron diffraction, and it is how a gas, a liquid and a crystal are distinguished mathematically. Drag the temperature and density sliders (or jump to a gas/liquid/solid preset) and watch the box melt, condense or order itself while the g(r) plot, coordination number, instantaneous temperature and virial pressure update in real time.