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MD Keywords

To perform a molecular dynamics calculation set the task parameter 

task : md

To control the length of the dynamics simulation

  • md_num_iter : number of MD steps (default 100)
  • md_delta_t : MD timestep (default 1fs)

To control the conditions for the dynamics

  • md_ensemble : Ensemble (NVE, NVT, NPH, NPT, HUG)
  • md_thermostat : Thermostat to use if not a constant energy ensemble. values: NOSE-HOOVER (default), LANGEVIN, HOOVER-LANGEVIN
  • md_barostat : Barostat to use if not a constant volume ensemble. Values: ANDERSEN-HOOVER (default), PARRINELLO-RAHMAN
  • md_temperature : Temperature to use if not a constant energy ensemble

For the Hugoniot Thermostat

  • md_hug_method : Hugoniostat method. Values: NONE (default), NVHUG, NPHUG
  • md_hug_dir : Hugoniostat compression direction. Values: XDIR, YDIR, ZDIR, ISO (default)
  • md_hug_t : Hugoniostat coupling constant.
  • md_hug_compression : Hugoniostat compression ratio. Values from 0.0 to 1.0 (default)

Path Integral MD (PIMD)

  • MD_USE_PATHINT PIMD on/off
  • MD_NUM_BEADS PIMD number of beads
  • MD_PATHINT_INIT PIMD initialisation method
  • MD_PATHINT_STAGING PIMD staging modes on/off
  • MD_PATHINT_NUM_STAGES PIMD number of stages

Advanced settings

It is possible to change the tolerances for accepting the SCF groundstate during the molecular dynamics run. The default value are those for a single point energy e.g. the default for md_elec_energy_tol is the value of elec_energy_tol

  • md_elec_energy_tol : MD total energy per atom convergence tolerance
  • md_elec_eigenvalue_tol : MD eigenvalue convergence tolerance
  • md_elec_force_tol : max force per atom convergence tolerance

  • md_elec_convergence_win : MD convergence tolerance window

  • MD_EQM_METHOD MD enhanced equilibration method

  • MD_EQM_ION_T MD equilibration time for ions
  • MD_EQM_CELL_T MD equilibration time for cell
  • MD_EQM_T MD equilibration time
  • MD_ION_T MD characteristic ionic time

  • MD_CELL_T MD characteristic cell time

  • MD_CELL_DAMP_RINGING Damp cell ringing mode

  • MD_USE_PLUMED Use PLUMED metadynamics