# HIRSHFELD_CONSTRAINT

Parameters for CDFT with a Gaussian Hirshfeld constraint. [Edit on GitHub]

## Keywords

- ATOMIC_CUTOFF

- ATOMIC_RADII

- ATOMS_MEMORY

- EPS_CUTOFF

- GAUSSIAN_RADIUS

- GAUSSIAN_SHAPE

- PRINT_DENSITY

- SHAPE_FUNCTION

- USE_ATOMIC_CUTOFF

- USE_BOHR

## Keyword descriptions

ATOMIC_CUTOFF: real = 1.00000000E-012

  Usage: ATOMIC_CUTOFF {real}

  Numerical cutoff for calculation of Hirshfeld densities. [Edit on GitHub]

ATOMIC_RADII: real[ ] = [angstrom]

  Usage: ATOMIC_RADII {real} {real} {real}

  Defines custom radii to setup the spherical Gaussians. Give one value per element in the same order as they appear in the input coordinates. [Edit on GitHub]

ATOMS_MEMORY: integer = 80

  Usage: ATOMS_MEMORY

  Number of atomic gradients to store in memory. [Edit on GitHub]

EPS_CUTOFF: real = 1.00000000E-012

  Usage: EPS_CUTOFF {real}

  Numerical cutoff for calculation of weight function. [Edit on GitHub]

GAUSSIAN_RADIUS: real = 3.00000000E+000 [angstrom]

  Usage: GAUSSIAN_RADIUS <REAL>

  Radius parameter controlling the creation of Gaussians. [Edit on GitHub]

GAUSSIAN_SHAPE: enum = DEFAULT

  Usage: GAUSSIAN_SHAPE (SINGLE|VDW|COVALENT|USER)

  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 GAUSSIAN_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.

  Mentions: ⭐Constrained DFT

  Specifies the type of Gaussian used for SHAPE_FUNCTION GAUSSIAN. [Edit on GitHub]

PRINT_DENSITY: logical = F

  Lone keyword: `T`

  Usage: PRINT_DENSITY TRUE

  Logical to control printing of Hirshfeld densities to .cube file. [Edit on GitHub]

SHAPE_FUNCTION: enum = GAUSSIAN

  Usage: SHAPE_FUNCTION {Gaussian,Density}

  Valid values:

  - `GAUSSIAN` One Gaussian per atom with radius determined by the keyword GAUSSIAN_SHAPE.

  - `DENSITY` Atomic density expanded in terms of multiple Gaussians.

  Mentions: ⭐Constrained DFT

  Type of shape function used for Hirshfeld partitioning. [Edit on GitHub]

USE_ATOMIC_CUTOFF: logical = T

  Lone keyword: `T`

  Usage: USE_ATOMIC_CUTOFF TRUE

  Logical to control use of ATOMIC_CUTOFF. [Edit on GitHub]

USE_BOHR: logical = F

  Lone keyword: `T`

  Usage: USE_BOHR .TRUE.

  Convert the Gaussian radius from angstrom to bohr. This results in a larger Gaussian than without unit conversion. [Edit on GitHub]