Section ATOM_GROUP

• Define a group of atoms for use in a Becke constraint. Each repetition of this section creates a new constraint.

• Section path: CP2K_INPUT / FORCE_EVAL / PROPERTIES / ET_COUPLING / BECKE_CONSTRAINT_A / ATOM_GROUP

• This section can be repeated.

• Subsections

  • none

• Keywords

  • ATOMS
  • COEFF
  • CONSTRAINT_TYPE
  • FRAGMENT_CONSTRAINT

• Keyword descriptions

  ATOMS
  	ATOMS {Integer} ...
  	Specifies the list of atoms that are included in the constraint group.
  	This keyword cannot be repeated and it expects a list of integers.

  COEFF
  	COEFF {Real} ...
  	Defines coefficients for the atoms in the list of atoms. Accepts value +/-1.0.
  	This keyword can be repeated and it expects a list of reals.

  CONSTRAINT_TYPE
  	CONSTRAINT_TYPE {Keyword}
  	Determines what type of constraint to apply.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: CHARGE
  	List of valid keywords: ALPHA Alpha spin density constraint. BETA Beta spin density constraint. CHARGE Total charge density constraint (rho_alpha + rho_beta). MAGNETIZATION Magnetization density constraint (rho_alpha - rho_beta).

  FRAGMENT_CONSTRAINT
  	FRAGMENT_CONSTRAINT {Logical}
  	Use a fragment based constraint. Takes as input the electron densities of two isolated fragments in the same geometry that they have in the full system. The isolated fragment densities are read from cube files defined in FRAGMENT_{A,B}_FILE. For magnetization density constraints, additional files containing the spin difference densities must be defined with the keywords FRAGMENT_{A,B}_SPIN_FILE. With this keyword active, the target value of the constraint is calculated from the the superposition of the isolated fragment densities. Supports only static calculations.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.