LennardJones

LennardJonesPotential #

The well-known Lennard-Jones potential.

\[U(r) = 4\epsilon \left[\left(\frac{\sigma}{r}\right)^{12} - \left(\frac{\sigma}{r}\right)^6\right]\]

Example #

[[forcefields.global]]
interaction = "Pair"
potential   = "LennardJones"
ignore.molecule = "Nothing"
ignore.particles_within.bond    = 3
ignore.particles_within.contact = 1
spatial_partition = {type = "CellList", margin = 0.2}

cutoff = 2.5
parameters = [
    {index = 0, offset = 100, sigma = 2.0, epsilon = 10.0},
]

Input Reference #

To calculate \( \sigma \) and \( \epsilon \) for each pair, Lorentz-Berthelot combining rules are used.

\[\sigma_{ij} = \frac{\sigma_i + \sigma_j}{2} \\ \epsilon_{ij} = \sqrt{\epsilon_i\epsilon_j}\]
  • cutoff: Floating (Optional. By default, 2.5.)
    • The cutoff distance relative to the maximum \(\sigma_{ij}\) .
  • index: Integer
    • The index of the particle.
  • offset: Integer (ptional. By default, 0.)
    • Offset value of the index.
  • sigma: Floating
    • It determines the effective particle size.
  • epsilon: Integer
    • It determines the strength of the potential.

For other values, see Pair.