md.integrators.RingPolymer

class md.integrators.RingPolymer(*args: Any, **kwargs: Any)

Integrator for ring polymer molecular dynamics, as e.g. described in [1]

During the main step, ring polymer positions and momenta are transformed from bead to normal mode representation, propagated deterministically and then transformed back. Needs the number of beads and the ring polymer temperature in order to initialize the propagator matrix. The integrator reverts to standard velocity Verlet integration if only one bead is used.

Uses atomic units of time internally.

Parameters:

• time_step (float) – Time step in femto seconds.

• n_beads (int) – Number of beads in the ring polymer.

• temperature (float) – Ring polymer temperature in Kelvin.

References

[1]

Ceriotti, Parrinello, Markland, Manolopoulos: Efficient stochastic thermostatting of path integral molecular dynamics. The Journal of Chemical Physics, 133, 124105. 2010.