Steric

The Steric potential is used to model steric interactions between particles. It is typically represented as a power law repulsion, which can be useful for preventing overlap between particles or modeling excluded volume effects.

There are two types of Steric potentials implemented:

Steric6

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

Steric12

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

where:

  • \(\epsilon\) is the strength of the interaction

  • \(\sigma\) is the characteristic distance

  • \(r\) is the distance between the particles

  • type: Bond2, Steric6 or Steric12

  • parameters: None

  • data:

    • id_i: int: Id of one particle

    • id_j: int: Id of the other particle

    • epsilon: real: Strength of the interaction \([energy]\)

    • sigma: real: Characteristic distance \([distance]\)

Example (for Steric6):

"steric6Bonds":{
  "type":["Bond2","Steric6"],
  "parameters":{},
  "labels":["id_i", "id_j", "epsilon", "sigma"],
  "data":[[0, 1, 1.0, 1.0],
          [1, 2, 0.8, 1.1],
          [2, 3, 1.2, 0.9]]
}

Steric6Common_epsilon_sigma

Steric6 bonds variant with common parameters (epsilon and sigma) for all bonds.

  • type: Bond2, Steric6Common_epsilon_sigma

  • parameters:

    • epsilon: real: Common strength of the interaction for all bonds \([energy]\)

    • sigma: real: Common characteristic distance for all bonds \([distance]\)

  • data:

    • id_i: int: Id of one particle

    • id_j: int: Id of the other particle

Example:

"steric6BondsCommonEpsilonSigma":{
  "type":["Bond2","Steric6Common_epsilon_sigma"],
  "parameters":{"epsilon":1.0,
                "sigma":1.0},
  "labels":["id_i", "id_j"],
  "data":[[0, 1],
          [1, 2],
          [2, 3]]
}

Note: Similar variants (Steric12 and Steric12Common_epsilon_sigma) are available for the Steric12 potential.