HarmonicAngular

The HarmonicAngular potential is a simple model for angular bonds that applies a harmonic restraint on the angle between three particles.

\[U = \frac{1}{2}K(\theta - \theta_0)^2\]

where:

• \(K\) is the angular spring constant

• \(\theta\) is the current angle between the three particles

• \(\theta_0\) is the equilibrium angle

---

• type: Bond3, HarmonicAngular

• parameters: None

• data:

  • id_i: int: Id of the first particle

  • id_j: int: Id of the central particle

  • id_k: int: Id of the third particle

  • K: real: Angular spring constant \([energy]/[angle]^2\)

  • theta0: real: Equilibrium angle \([angle]\)

Example:

"harmonicAngularBonds":{
  "type":["Bond3","HarmonicAngular"],
  "parameters":{},
  "labels":["id_i", "id_j", "id_k", "K", "theta0"],
  "data":[[0, 1, 2, 100.0, 1.57],
          [1, 2, 3, 100.0, 1.57],
          [2, 3, 4, 100.0, 1.57]]
}

HarmonicAngularCommon_K

HarmonicAngular bonds variant with a common angular spring constant (K) for all bonds.

---

• type: Bond3, HarmonicAngularCommon_K

• parameters:

  • K: real: Common angular spring constant for all bonds \([energy]/[angle]^2\)

• data:

  • id_i: int: Id of the first particle

  • id_j: int: Id of the central particle

  • id_k: int: Id of the third particle

  • theta0: real: Equilibrium angle \([angle]\)

Example:

"harmonicAngularBondsCommonK":{
  "type":["Bond3","HarmonicAngularCommon_K"],
  "parameters":{"K":100.0},
  "labels":["id_i", "id_j", "id_k", "theta0"],
  "data":[[0, 1, 2, 1.57],
          [1, 2, 3, 1.57],
          [2, 3, 4, 1.57]]
}

HarmonicAngularCommon_K_theta0

HarmonicAngular bonds variant with common parameters (K and theta0) for all bonds.

---

• type: Bond3, HarmonicAngularCommon_K_theta0

• parameters:

  • K: real: Common angular spring constant for all bonds \([energy]/[angle]^2\)

  • theta0: real: Common equilibrium angle for all bonds \([angle]\)

• data:

  • id_i: int: Id of the first particle

  • id_j: int: Id of the central particle

  • id_k: int: Id of the third particle

Example:

"harmonicAngularBondsCommonKTheta0":{
  "type":["Bond3","HarmonicAngularCommon_K_theta0"],
  "parameters":{"K":100.0,
                "theta0":1.57},
  "labels":["id_i", "id_j", "id_k"],
  "data":[[0, 1, 2],
          [1, 2, 3],
          [2, 3, 4]]
}