Animation of a noble gas

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JavaScript animated nobel gas


The JavaScript-animation shows a two-dimensional molecular dynamics simulation with a Lennard-Jones-potential force. The Lennard-Jones potential energy is U(r) = ε · (r0/r)12 - 2ε · (r0/r)6.     r0 is the equilibrium distance between the atomic nuclei (no net force) and ε is the depth of the potential. The force is F(r) = -dU/dr (Van der Waals for longer distances). The depth ε is proportional to a temperature T0 = ε/k, where k is the Boltzmann-constant. The mean kinetic energy of a free particle is 1/2·mvx2 = 1/2·mvy2 = 1/2·kT. For Argon we have T0 = 124 K and r0 = 384 pm. The argon atom has an empirical radius of 71 pm ( The most common isotope (Ar-40) has a mass of 39.962 u. The movement is restricted to two dimensions. The Euler-Cromer method is used for numerical integration. The time-step is chosen such that the particles move about 0.1 pixel per frame.

May 8th, 2022, Lie.