EXTERNAL_POTENTIAL

Section controlling the presence of an electrostatic external potential dependent on the atomic positions (X,Y,Z). As the external potential is currently applied via a grid, it only works with DFT based methods (GPW/GAPW) that already use a grid based approach to solve the Poisson equation. [Edit on GitHub]

Subsections

• MAXWELL

Keywords

• DX

• ERROR_LIMIT

• FUNCTION

• PARAMETERS

• READ_FROM_CUBE

• SCALING_FACTOR

• STATIC

• UNITS

• VALUES

Keyword descriptions

DX

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

Description: Parameter used for computing the derivative with the Ridders’ method.

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ERROR_LIMIT

Type: real
Default: 1.00000000E-012
Usage: ERROR_LIMIT

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.

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FUNCTION

Type: string
Usage: FUNCTION X^2+Y^2+Z^2+LOG(ABS(X+Y))

Description: Specifies the functional form in mathematical notation. Variables must be the atomic coordinates (X,Y,Z) of the grid.

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PARAMETERS

Type: string[ ]
Repeatable: yes
Usage: PARAMETERS a b D

Description: Defines the parameters of the functional form

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READ_FROM_CUBE

Type: logical
Default: F
Lone keyword: T
Usage: READ_FROM_CUBE T

Description: Switch for reading the external potential from file pot.cube. The values of the potential must be on the grid points of the realspace grid. Whitespace-separated cube values are accepted. If adjacent values are written without whitespace, each value must occupy a 13-character E13.5 field, as in CP2K-generated cube files.

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SCALING_FACTOR

Type: real
Default: 1.00000000E+000
Usage: SCALING_FACTOR

Description: A factor for scaling the the external potential that is read from file. The value of the potential at each grid point is multiplied by this factor.

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STATIC

Type: logical
Default: T
Lone keyword: T
Usage: STATIC T

Description: Specifies the external potential as STATIC or time dependent. At the moment only static potentials are implemented.

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UNITS

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

Description: 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.

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VALUES

Type: real[ ]
Default: [internal_cp2k]
Repeatable: yes
Usage: VALUES

Description: Defines the values of parameter of the functional form

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