BECKE_CONSTRAINT

References: Becke1988b

Define settings influencing the construction of the Becke weight function. [Edit on GitHub]

Keywords

Keyword descriptions

ADJUST_SIZE

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

Description: Adjust Becke cell boundaries with atomic radii to generate a heteronuclear cutoff profile. These radii are defined with the keyword ATOMIC_RADII.

Mentions: ⭐Constrained DFT

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ATOMIC_RADII

Type: real[ ]
Default: [angstrom]
Usage: ATOMIC_RADII {real} {real} {real}

Description: Defines atomic radii to generate a heteronuclear cutoff profile. Give one value per element in the same order as they appear in the input coordinates.

Mentions: ⭐Constrained DFT

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CAVITY_CONFINE

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

Description: Activates Gaussian cavity confinement. The constraint is evaluated only inside the cavity. The cavity is formed by summing spherical Gaussians centered on the constraint atoms.

Mentions: ⭐Constrained DFT

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CAVITY_PRINT

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

Description: Print cavity in Gaussian cube file format. Currently, printing options are hardcoded.

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CAVITY_RADIUS

Type: real
Default: 3.00000000E+000 [angstrom]
Usage: CAVITY_RADIUS

Description: Radius parameter controlling the creation of Gaussian cavity confinement.

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CAVITY_SHAPE

Type: enum
Default: DEFAULT
Usage: CAVITY_SHAPE (SINGLE|VDW|COVALENT|USER)

Description: Specifies the type of Gaussian cavity used.

Valid values:

  • DEFAULT Use covalent radii (in angstrom) to construct Gaussians, but fixed 1.0_dp radius for elements with a radius larger than this value.

  • SINGLE Single Gaussian for all atom types with radius given by CAVITY_RADIUS.

  • VDW Use van der Waals radii to construct Gaussians.

  • COVALENT Use covalent radii to construct Gaussians.

  • USER Use user defined radii (keyword ATOMIC_RADII) to construct Gaussians.

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CAVITY_USE_BOHR

Type: logical
Default: F
Lone keyword: T
Usage: CAVITY_USE_BOHR TRUE

Description: Convert the cavity radius from angstrom to bohr. This results in a larger confinement cavity than without unit conversion.

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CUTOFF_TYPE

Type: enum
Default: GLOBAL
Usage: CUTOFF_TYPE (GLOBAL|ELEMENT)

Description: Specifies the type of cutoff used when building the Becke weight function.

Valid values:

  • GLOBAL Use a single value for all elements. Read from GLOBAL_CUTOFF.

  • ELEMENT Use a different value for all elements. Values read from ELEMENT_CUTOFF.

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ELEMENT_CUTOFF

Type: real[ ]
Default: [angstrom]
Usage: ELEMENT_CUTOFF {real} {real} {real}

Description: Defines element specific cutoffs to decide which atoms contribute to the weight function at each real space grid point. Give one value per element in the same order as they appear in the coordinates.

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EPS_CAVITY

Type: real
Default: 1.00000000E-006
Usage: EPS_CAVITY {real}

Description: Density threshold for cavity creation. Grid points where the Gaussian density falls below the threshold are ignored.

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GLOBAL_CUTOFF

Type: real
Default: 3.17506325E+000 [angstrom]
Usage: GLOBAL_CUTOFF

Description: Parameter used to select which atoms contribute to the weight function at each real space grid point.

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IN_MEMORY

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

Description: Precompute gradients due to Becke constraint during initial formation of constraint and store them in memory. Useful in combination with confinement, memory intensive otherwise. Does nothing if forces are not calculated.

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SHOULD_SKIP

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

Description: If grid point is farther than GLOBAL_CUTOFF from all constraint atoms, move directly to next grid point, thus saving computational resources.

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