The Lennard-Jones potential

The good old classic Lennard-Jones potential. Be aware that it does not describe real systems very well, except for the famous material Lennardjonesium, widely described in the scientific literature. :-)

The Lennard-Jones calculator, LJPotential, takes a number of parameters

LennardJones(elements, epsilon, sigma, rCut=-1, modified=True,
             verbose=None)

elements: A list of these elements (their atomic numbers). You do not need to use “real” atomic numbers, 0,1,2,… will do just nicely if you do not model real elements.

epsilon and sigma: The Lennard-Jones parameters. These should be given as NxN symmetric or lower triangular matrices if there are N elements. The diagonal elements are for same-element interactions, the off-diagonal ones are for interactions between elements.

rCut: The cutoff length. Default: 3 times the largest value of sigma.

modified: If true, a constant is subtracted from the potential energy, so it is zero at the cutoff.

Nano-FAQ

Q: What are good Lennard-Jones parameters for copper?

A: There are no good Lennard-Jones parameters for copper! If you want to model a real material, do not use a toy potential.