EXTERNAL_POTENTIAL

Section can be repeated.

Section controlling the presence of an external potential dependent on the atomic positions (X,Y,Z). Not to be confused with the Quickstep DFT-specific settings under FORCE_EVAL/DFT/EXTERNAL_POTENTIAL.

The following 3 symbol(s) will be reserved as the variable(s) to be substituted for internal evaluation: X, Y, Z. They cannot be used as parameters. [Edit on GitHub]

Keywords

• ATOMS_LIST

• DX

• ERROR_LIMIT

• FUNCTION

• PARAMETERS

• UNITS

• VALUES

Keyword descriptions

ATOMS_LIST

Type: integer[ ]
Repeatable: yes
Usage: ATOMS_LIST {INT} {INT} ..

Description: Specifies the atoms on which the external potential will act [Edit on GitHub]

DX

Type: real
Default: 1.00000000E-001 [bohr]
Usage: DX <REAL>

Description: Parameter used for computing the derivative with the Ridders’ method. [Edit on GitHub]

ERROR_LIMIT

Type: real
Default: 1.00000000E-012
Usage: ERROR_LIMIT <REAL>

Description: Checks that the error in computing the derivative is not larger than the value set; in case error is larger a warning message is printed. [Edit on GitHub]

FUNCTION

Type: string
Value must be double-quoted if followed by inline comments.
Usage: FUNCTION A*X+B*(2/(1+EXP(-0.001*Y))-1)

Description: Specifies a functional form. The maximum length is 1024 characters. Mathematical Operators recognized are +, -, *, /, ^ or alternatively **, whereas symbols for brackets must be (). The function parser recognizes the Fortran 90 intrinsic functions abs, min, max, exp, log10, log, sqrt, sinh, cosh, tanh, sin, cos, tan, asin, acos, atan2, atan, erf, erfc. Parsing for intrinsic functions is not case sensitive. [Edit on GitHub]

PARAMETERS

Type: string[ ]
Repeatable: yes
Usage: PARAMETERS A B

Description: Defines the symbols for the parameter(s) in the functional form, delimited by whitespaces. Symbols are case sensitive and each is at most 80 characters long. [Edit on GitHub]

UNITS

Type: string[ ]
Repeatable: yes
Usage: UNITS eV*angstrom^-1 angstrom

Description: Optionally, defines CP2K unit string for each of the given parameter value(s). A valid CP2K unit string is one of the strings that is listed under the References/Units section of the CP2K manual, or a combination of multiple of these strings with *, / and ^. It is assumed that the corresponding parameter value is specified in this unit which needs to be converted first to the internal unit during input parsing. Note that the meaningfulness of the unit is not checked. If omitted, all values will be treated as already in the internal unit and used literally. [Edit on GitHub]

VALUES

Type: real[ ]
Default: [internal_cp2k]
Repeatable: yes
Usage: VALUES 50 1.0E+2

Description: Defines the value(s) of the parameter in the functional form. [Edit on GitHub]