Section MD

• This section defines the whole set of parameters needed perform an MD run.

• Section path: CP2K_INPUT / MOTION / MD

• This section cannot be repeated.

• Subsections

  • ADIABATIC_DYNAMICS
  • AVERAGES
  • BAROSTAT
  • CASCADE
  • INITIAL_VIBRATION
  • LANGEVIN
  • MSST
  • PRINT
  • REFTRAJ
  • RESPA
  • SHELL
  • THERMAL_REGION
  • THERMOSTAT
  • VELOCITY_SOFTENING

• Keywords

  • ANGVEL_TOL
  • ANGVEL_ZERO
  • ANNEALING
  • ANNEALING_CELL
  • COMVEL_TOL
  • DISPLACEMENT_TOL
  • ECONS_START_VAL
  • ENSEMBLE
  • INITIALIZATION_METHOD
  • MAX_STEPS
  • SCALE_TEMP_KIND
  • STEPS
  • STEP_START_VAL
  • TEMPERATURE
  • TEMPERATURE_ANNEALING
  • TEMP_KIND
  • TEMP_TOL
  • TIMESTEP
  • TIME_START_VAL

• Keyword descriptions

  ANGVEL_TOL
  	ANGVEL_TOL {Real}
  	The maximum accepted angular velocity. This option is ignored when the system is periodic. Removes the components of the velocities thatproject on the external rotational degrees of freedom.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default unit: [au_t^-1*bohr]

  ANGVEL_ZERO
  	ANGVEL_ZERO {Logical}
  	Set the initial angular velocity to zero. This option is ignored when the system is periodic or when initial velocities are defined. Technically, the part of the random initial velocities that projects on the external rotational degrees of freedom is subtracted.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  ANNEALING
  	ANNEALING {Real}
  	Specifies the rescaling factor for annealing velocities. Automatically enables the annealing procedure. This scheme works only for ensembles that do not have thermostats on particles.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E+000

  ANNEALING_CELL
  	ANNEALING_CELL {Real}
  	Specifies the rescaling factor for annealing velocities of the CELL Automatically enables the annealing procedure for the CELL. This scheme works only for ensambles that do not have thermostat on CELLS velocities.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E+000

  COMVEL_TOL
  	COMVEL_TOL {Real}
  	The maximum accepted velocity of the center of mass. With Shell-Model, comvel may drift if MD%THERMOSTAT%REGION /= GLOBAL
  	This keyword cannot be repeated and it expects precisely one real.
  	Default unit: [au_t^-1*bohr]

  DISPLACEMENT_TOL
  	DISPLACEMENT_TOL {Real}
  	This keyword sets a maximum atomic displacement in each Cartesian direction.The maximum velocity is evaluated and if it is too large to remainwithin the assigned limit, the time step is rescaled accordingly,and the first half step of the velocity verlet is repeated.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 5.29177209E+001
  	Default unit: [angstrom]

  ECONS_START_VAL
  	ECONS_START_VAL {Real}
  	The starting value of the conserved quantity
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [hartree]

  ENSEMBLE
  	ENSEMBLE {Keyword}
  	The ensemble/integrator that you want to use for MD propagation
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: NVE
  	List of valid keywords: HYDROSTATICSHOCK simulate steady shock with hydrostatic pressure ISOKIN constant kinetic energy LANGEVIN langevin dynamics (constant temperature) MSST simulate steady shock (uniaxial) MSST_DAMPED simulate steady shock (uniaxial) with extra viscosity NPE_F constant pressure ensemble (no thermostat) NPE_I constant pressure ensemble using an isotropic cell (no thermostat) NPT_F constant temperature and pressure using a flexible cell NPT_I constant temperature and pressure using an isotropic cell NPT_IA NPT_I ensemble with frozen atoms in absolute coordinate NVE constant energy (microcanonical) NVT constant temperature and volume (canonical) NVT_ADIABATIC adiabatic dynamics in constant temperature and volume ensemble (CAFES) REFTRAJ reading frames from a file called reftraj.xyz (e.g. for property calculation)
  	This keyword cites the following references: [EVANS1983] [Minary2003] [VandeVondele2002]

  INITIALIZATION_METHOD
  	INITIALIZATION_METHOD {Keyword}
  	This keyword selects which method to use to initialize MD. If velecities are not set explicitly, DEFAULT optioin will assign random velocities and then scale according to TEMPERATURE; VIBRATIONAL option will then use previously calculated vibrational modes to initialise both the atomic positions and velocities so that the starting point for MD is as close to canonical ensemble as possible, without the need for lengthy equilibration steps. See PRL 96, 115504 (2006). The user input atomic positions in this case are expected to be already geometry optimised. Further options for VIBRATIONAL mode is can be set in INITIAL_VIBRATION subsection. If unspecified, then the DEFAULT mode will be used.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: DEFAULT
  	List of valid keywords: DEFAULT Assign random velocities and then scale according to TEMPERATURE VIBRATIONAL Initialise positions and velocities to give canonical ensemble with TEMPERATURE, using the method described in PRL 96, 115504 (2006)

  MAX_STEPS
  	MAX_STEPS {Integer}
  	The number of MD steps to perform, counting from step 1
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 1000000000

  SCALE_TEMP_KIND
  	SCALE_TEMP_KIND {Logical}
  	When necessary rescale the temperature per each kind separately
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  STEPS
  	STEPS {Integer}
  	The number of MD steps to perform, counting from step_start_val.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 3

  STEP_START_VAL
  	STEP_START_VAL {Integer}
  	The starting step value for the MD
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 0

  TEMPERATURE
  	TEMPERATURE {Real}
  	The temperature in K used to initialize the velocities with init and pos restart, and in the NPT/NVT simulations
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 3.00000000E+002
  	Default unit: [K]

  TEMPERATURE_ANNEALING
  	TEMPERATURE_ANNEALING {Real}
  	Specifies the rescaling factor for the external temperature.This scheme works only for the Langevin ensemble.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E+000

  TEMP_KIND
  	TEMP_KIND {Logical}
  	Compute the temperature per each kind separately
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  TEMP_TOL
  	TEMP_TOL {Real}
  	The maximum accepted deviation of the (global) temperaturefrom the desired target temperature before a rescaling of the velocites is performed. If it is 0 no rescaling is performed. NOTE: This keyword is obsolescent; Using a CSVR thermostat with a short timeconstant is recommended as a better alternative.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [K]
  	Alias names for this keyword: TEMP_TO, TEMPERATURE_TOLERANCE

  TIMESTEP
  	TIMESTEP {Real}
  	The length of an integration step (in case RESPA the large TIMESTEP)
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 5.00000000E-001
  	Default unit: [fs]

  TIME_START_VAL
  	TIME_START_VAL {Real}
  	The starting timer value for the MD
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [fs]