The CP2K project : input section MD

Section MD

Index of all sections. This section is located at __ROOT__%MOTION%MD.

This section defines the whole set of parameters needed perform an MD run. This section can not be repeated and can not be optional.

Subsections

Section keywords

Keyword descriptions

ENSEMBLE
ensemble nve
The ensemble/integrator that you want to use for MD propagation
This optional keyword expects a keyword. Default value: NVE
valid keywords:
  • NVE: constant energy (microcanonical)
  • NVT: constant temperature and volume (canonical)
  • NPT_I: constant temperature and pressure using an isotropic cell
  • NPT_F: constant temperature and pressure using a flexible cell
  • MSST: simulate steady shock (uniaxial)
  • MSST_DAMPED: simulate steady shock (uniaxial) with extra viscosity
  • HYDROSTATICSHOCK: simulate steady shock with hydrostatic pressure
  • ISOKIN: constant kinetic energy
  • REFTRAJ: reading frames from a file called reftraj.xyz (e.g. for property calculation)
  • LANGEVIN: langevin dynamics (constant temperature)
  • NPE_F: constant pressure ensemble (no thermostat)
  • NPE_I: constant pressure ensemble using an isotropic cell (no thermostat)

This keyword cites following references: [EVANS1983] [Minary2003] [Kolafa2004]
STEPS
steps 100
The number of MD steps to perform
This optional keyword expects an integer. Default value: 3
TIMESTEP
timestep 1.0
The length of an integration step (in case RESPA the large TIMESTEP)
This optional keyword expects a real. Default unit: [fs], default value: 4.9999999999999994E-01 fs
STEP_START_VAL
step_start_val
The starting step value for the MD
This optional keyword expects an integer. Default value: 0
TIME_START_VAL
time_start_val
The starting timer value for the MD
This optional keyword expects a real. Default unit: [fs], default value: 0.0000000000000000E+00 fs
ECONS_START_VAL
econs_start_val
The starting value of the conserved quantity
This optional keyword expects a real. Default unit: [hartree], default value: 0.0000000000000000E+00 hartree
TEMPERATURE
temperature 325.0
The temperature in K used to initialize the velocities with init and pos restart, and in the NPT/NVT simulations
This optional keyword expects a real. Default unit: [K], default value: 3.0000000000000000E+02 K
TEMP_TOL
temp_tol 0.0
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 optional keyword expects a real. Default unit: [K], default value: 0.0000000000000000E+00 K
variants: TEMP_TO, TEMPERATURE_TOLERANCE
TEMP_KIND
temp_kind LOGICAL
Compute the temperature per each kind separately
This optional keyword expects a logical
This keyword behaves as a switch T . Default value: F
SCALE_TEMP_KIND
scale_temp_kind LOGICAL
When necessary rescale the temperature per each kind separately
This optional keyword expects a logical
This keyword behaves as a switch T . Default value: F
COMVEL_TOL
comvel_tol 0.0
The maximum accepted velocity of the center of massIf it is 0 no subtraction is performed. With Shell-Model, comvel may drift if MD%THERMOSTAT%REGION /= GLOBAL
This optional keyword expects a real. Default value: 0.0000000000000000E+00
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 optional keyword expects a logical
This keyword behaves as a switch T . Default value: F
ANNEALING
annealing
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 optional keyword expects a real. Default value: 1.0000000000000000E+00
ANNEALING_CELL
ANNEALING_CELL
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 optional keyword expects a real. Default value: 1.0000000000000000E+00
DISPLACEMENT_TOL
DISPLACEMENT_TOL
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 optional keyword expects a real. Default unit: [angstrom], default value: 5.2917720859000006E+01 angstrom


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