Lennard-Jones Potential

Simple molecular dynamics model are often constructed using the Lennard-Jones potential.

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This simulation shows the dynamics of a particle of mass m within this potential.  You can drag particle to change its position and you can drag the energy-line to change its total energy.

The Lennard-Jones potential function is a reasonably accurate model of interactions between noble gas atoms.  The binding energy epsilon is the depth of the potential well and minimum molecular separation are set equal to unity.  This simulation uses uses a natural system of units the mass and the depth of the Lennard-Jones potential set equal to 1. For argon (for example), the unit of distance is 3.4 angstroms, the unit of mass is 40 atomic mass units, and the unit of energy is 0.01 electron-volts; the corresponding unit of time is then 2.2 picoseconds, the unit of velocity is 160 meters per second.

 

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The Lennard-Jones model was created by Wolfgang Christian using the Easy Java Simulations (Ejs) modeling tool and is designed to teach modeling.  Users can inspect and modify the underlying model by copying the model from the running program into Ejs.  Right click within the simulation to examine the model in Ejs. 

You can examine and modify this simulation if you have Ejs installed by right-clicking within a plot and selecting "Open Ejs Model" from the pop-up menu. Information about Ejs is available at: <http://www.um.es/fem/Ejs/>.

The Easy Java Simulations (EJS) manual can be downloaded from the ComPADRE Open Source Physics collection and from the Ejs website.

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