Periodic¶

class hoomd.md.improper.Periodic¶

Bases: Improper

Periodic improper force.

Periodic computes forces, virials, and energies on all impropers in the simulation state with:

\[U(\chi) = k \left( 1 + d \cos(n \chi - \chi_{0}) \right )\]

Example:

periodic = hoomd.md.improper.Periodic()
periodic.params["A-B-C-D"] = dict(k=1.0, n=1, chi0=0, d=1.0)

Members inherited from AutotunedObject:

property is_tuning_complete¶: Check if kernel parameter tuning is complete. Read more...

Members inherited from Force:

additional_virial¶: Additional virial tensor term \(W_\mathrm{additional}\). Read more...

energy¶: The potential energy \(U\) of the system from this force. Read more...

torques¶: The torque \(\vec{\tau}_i\) applied to each particle. Read more...

virials¶: Virial tensor contribution \(W_i\) from each particle. Read more...

Members defined in Periodic:

params¶

The parameter of the harmonic impropers for each improper type. The dictionary has the following keys:

k (float, required), potential constant \(k\) \([\mathrm{energy}]\).
chi0 (float, required), equilibrium angle \(\chi_0\) \([\mathrm{radian}]\).
n (int, required), periodic number \(n\) \([\mathrm{dimensionless}]\).
d (float, required), sign factor \(d\) \([\mathrm{dimensionless}]\).