The Lennard-Jones potential

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

class asap3.LennardJones(elements, epsilon, sigma, rCut=-1.0, modified=True, verbose=None)[source]

Lennard-Jones potential.

Parameters:

  • elements (sequence of int) – The elements that will be supported, given as atomic numbers.

  • epsilon (numpy.ndarray or float) – The Lennard-Jones energy parameter, as a 2D array with each dimension equal to the number of elements; only the lower triangular part is used. A 1D array obtained by flattening the corresponding 2D array is also accepted, but this is deprecated and incurs less runtime testing. If there is only one element, a number may be given.

  • sigma (numpy.ndarray or float) – The Lennard-Jones length parameter, in the same format as epsilon.

  • rCut (float, optional) – The cutoff distance. A negative value (the default) selects the built-in default cutoff.

  • modified (bool, optional) – Whether the potential should be shifted so no jump occurs at the cutoff. The default is True.

  • verbose (bool, optional) – Print information while calculating. Defaults to the global Asap verbosity.

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.