Section FORCEFIELD

• Section specifying information regarding how to set up properly a force_field for the classical calculations.

• Section path: CP2K_INPUT / FORCE_EVAL / MM / FORCEFIELD

• This section cannot be repeated and cannot be optional.

• Subsections

  • BEND
  • BOND
  • CHARGE
  • CHARGES
  • DIPOLE
  • IMPROPER
  • NONBONDED
  • NONBONDED14
  • OPBEND
  • QUADRUPOLE
  • SHELL
  • SPLINE
  • TORSION

• Keywords

  • DO_NONBONDED
  • EI_SCALE14
  • IGNORE_MISSING_CRITICAL_PARAMS
  • MULTIPLE_POTENTIAL
  • PARMTYPE
  • PARM_FILE_NAME
  • SHIFT_CUTOFF
  • VDW_SCALE14
  • ZBL_SCATTERING

• Keyword descriptions

  DO_NONBONDED
  	DO_NONBONDED T
  	Controls the computation of all the real-sapce (short-range) nonbonded interactions. This also includes the real-space corrections for excluded or scaled 1-2, 1-3 and 1-4 interactions. When set to F, the neighborlists are not created and all interactions that depend on them are not computed.
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .TRUE.

  EI_SCALE14
  	EI_SCALE14 1.0
  	Scaling factor for the electrostatics 1-4
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+00

  IGNORE_MISSING_CRITICAL_PARAMS
  	IGNORE_MISSING_BOND_PARAMS T
  	Do not abort when critical force-field parameters are missing. CP2K will run as if the terms containing the missing parameters are zero.
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  MULTIPLE_POTENTIAL
  	MULTIPLE_POTENTIAL T
  	Enables the possibility to define NONBONDED and NONBONDED14 as a sum of different kinds of potential. Useful for piecewise defined potentials.
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  PARMTYPE
  	PARMTYPE {OFF,CHM,G87,G96}
  	Define the kind of torsion potential
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: OFF
  	List of valid keywords: AMBER Provides force field parameters through an external file with AMBER format (from v.8 on) CHM Provides force field parameters through an external file with CHARMM format G87 Provides force field parameters through an external file with GROMOS 87 format G96 Provides force field parameters through an external file with GROMOS 96 format OFF Provides force field parameters through the input file

  PARM_FILE_NAME
  	PARM_FILE_NAME {FILENAME}
  	Specifies the filename that contains the parameters of the FF.
  	This optional keyword cannot be repeated and it expects precisely one string.

  SHIFT_CUTOFF
  	SHIFT_CUTOFF <LOGICAL>
  	Add a constant energy shift to the real-space non-bonding interactions (both Van der Waals and electrostatic) such that the energy at the cutoff radius is zero. This makes the non-bonding interactions continuous at the cutoff.
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	Default value: .TRUE.

  VDW_SCALE14
  	VDW_SCALE14 1.0
  	Scaling factor for the VDW 1-4
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E+00

  ZBL_SCATTERING
  	ZBL_SCATTERING T
  	A short range repulsive potential is added, to simulatecollisions and scattering.
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.