Section EXTERNAL_POTENTIAL

• Section controlling the presence of an external potential dependent on the atomic positions (X,Y,Z)

• Section path: CP2K_INPUT / FORCE_EVAL / EXTERNAL_POTENTIAL

• This section can be repeated.

• Subsections

  • none

• Keywords

  • ATOMS_LIST
  • DX
  • ERROR_LIMIT
  • FUNCTION
  • PARAMETERS
  • UNITS
  • VALUES

• Keyword descriptions

  ATOMS_LIST
  	ATOMS_LIST {Integer} ... or a range {Integer}..{Integer}
  	Specifies the atoms on which the external potential will act
  	This keyword can be repeated and it expects a list of integers.

  DX
  	DX {Real}
  	Parameter used for computing the derivative with the Ridders method.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-01
  	Default unit: [bohr]

  ERROR_LIMIT
  	ERROR_LIMIT {Real}
  	Checks that the error in computing the derivative is not larger than the value set. In case prints a warning message.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-12

  FUNCTION
  	FUNCTION {String}
  	Specifies the functional form in mathematical notation. Variables must be the atomic coordinates (X,Y,Z).
  	This keyword cannot be repeated and it expects precisely one string.

  PARAMETERS
  	PARAMETERS {Word} ...
  	Defines the parameters of the functional form
  	This keyword can be repeated and it expects a list of words.

  UNITS
  	UNITS {Word} ...
  	Optionally, allows to define valid CP2K unit strings for each parameter value. It is assumed that the corresponding parameter value is specified in this unit.
  	This keyword can be repeated and it expects a list of words.

  VALUES
  	VALUES {Real} ...
  	Defines the values of parameter of the functional form
  	This keyword can be repeated and it expects a list of reals.
  	Default unit: [internal_cp2k]