The molecular dynamics implementation in CASTEP follows the Born-Oppenheimer approximation. i.e. forces are calculated from the ground state electronic configuration at each MD step. Within this scheme the NVE, NVT, NPH, and NPT ensembles can be simulated. Temperature control is implemented via a chain of Nosé-Hoover thermostats or by performing Langevin dynamics in the appropriate phase space. Hydrostatic pressure is regulated by the use of either an Andersen-Hoover or Parrinello-Rahman barostat. Any combination of these schemes is allowable within the limits of the desired ensemble.
A variety of user-specified or symmetry constraints can be imposed on the dynamics and these are discussed in 2.3. Check-pointing of MD calculations is discussed in section 2.5. Methods for speeding up MD calculations are described in section 2.7.
Variable cell calculations lead to issues with the plane wave basis set which CASTEP attempts to eliminate. This is discussed where relevant, i.e. in sections 2.2.3 and 2.6.