# PAIR_POTENTIAL

Section can be repeated.

Information on the pair potential to calculate dispersion [Edit on GitHub]

Subsections

- EEQ
- PRINT_DFTD

## Keywords

- ATOMPARM

- ATOM_COORDINATION_NUMBERS

- CALCULATE_C9_TERM

- D2_EXP_PRE

- D2_SCALING

- D3BJ_SCALING

- D3_EXCLUDE_KIND

- D3_EXCLUDE_KIND_PAIR

- D3_SCALING

- D4_CN_CUTOFF

- D4_CUTOFF

- D4_DEBUG

- D4_REFERENCE_CODE

- D4_SCALING

- EPS_CN

- FACTOR_S9_TERM

- KIND_COORDINATION_NUMBERS

- LONG_RANGE_CORRECTION

- MOLECULE_CORRECTION

- MOLECULE_CORRECTION_C8

- PARAMETER_FILE_NAME

- REFERENCE_C9_TERM

- REFERENCE_FUNCTIONAL

- R_CUTOFF

- SHORT_RANGE_CORRECTION

- SHORT_RANGE_CORRECTION_PARAMETERS

- TYPE

- VERBOSE_OUTPUT

## Keyword descriptions

ATOMPARM: string[ ]

  Keyword can be repeated.

  Usage: ATOMPARM <ELEMENT> <C6_parameter> <vdw_radii>

  Specifies parameters for atom types (in atomic units). If not provided default parameters are used (DFT-D2). [Edit on GitHub]

ATOM_COORDINATION_NUMBERS: string[ ]

  Keyword can be repeated.

  Usage: ATOM_COORDINATION_NUMBERS CN atom1 atom2 …

  Specifies the coordination number of a set of atoms for the C9 term in DFT-D3. [Edit on GitHub]

CALCULATE_C9_TERM: logical = F

  Lone keyword: `T`

  Usage: CALCULATE_C9_TERM

  Calculate C9 terms in DFT-D3 model [Edit on GitHub]

D2_EXP_PRE: real = 2.00000000E+001

  Aliases: EXP_PRE

  Usage: D2_EXP_PRE 20.

  Prefactor in exponential damping factor (DFT-D2 potential) [Edit on GitHub]

D2_SCALING: real = 0.00000000E+000

  Aliases: SCALING

  Usage: SCALING 0.2

  XC Functional dependent scaling parameter, if set to zero CP2K attempts to guess the xc functional that is in use and sets the associated scaling parameter. [Edit on GitHub]

D3BJ_SCALING: real[4] = 0.00000000E+000 0.00000000E+000 0.00000000E+000 0.00000000E+000

  Usage: D3BJ_SCALING 1.0 1.0 1.0 1.0

  XC Functional dependent scaling parameters (s6,a1,s8,a2) for the DFT-D3(BJ) method, if set to zero CP2K attempts to guess the xc functional from REFERENCE_FUNCTIONAL and sets the associated scaling parameter. [Edit on GitHub]

D3_EXCLUDE_KIND: integer[ ]

  Usage: D3_EXCLUDE_KIND kind1 kind2 …

  Specifies the atomic kinds excluded in the DFT-D3 calculation. [Edit on GitHub]

D3_EXCLUDE_KIND_PAIR: integer[2]

  Keyword can be repeated.

  Usage: D3_EXCLUDE_KIND_PAIR kind1 kind2

  Specifies the atomic kinds for interactions excluded from the DFT-D3 calculation. [Edit on GitHub]

D3_SCALING: real[3] = 0.00000000E+000 0.00000000E+000 0.00000000E+000

  Usage: D3_SCALING 1.0 1.0 1.0

  XC Functional dependent scaling parameters (s6,sr6,s8) for the DFT-D3 method, if set to zero CP2K attempts to guess the xc functional from REFERENCE_FUNCTIONAL and sets the associated scaling parameter. [Edit on GitHub]

D4_CN_CUTOFF: real = 5.29177209E+000 [angstrom]

  Usage: D4_CN_CUTOFF 30.0

  Coordination number cutoff for D4 [Edit on GitHub]

D4_CUTOFF: real = 1.05835442E+001 [angstrom]

  Usage: D4_CUTOFF 30.0

  Range of potential. The cutoff will be 2 times this value. Only used for the 2-body term of D4 [Edit on GitHub]

D4_DEBUG: logical = F

  Lone keyword: `T`

  Usage: D4_DEBUG

  Debug output for D4 method using reference code. [Edit on GitHub]

D4_REFERENCE_CODE: logical = T

  Lone keyword: `T`

  Usage: D4_REFERENCE_CODE

  Calculate D4 energy using external library. [Edit on GitHub]

D4_SCALING: real[4] = 0.00000000E+000 0.00000000E+000 0.00000000E+000 0.00000000E+000

  Usage: D4_SCALING 1.0 1.0 1.0 1.0

  XC Functional dependent scaling parameters (s6,a1,s8,a2) for the DFT-D4 method, if set to zero CP2K attempts to guess the xc functional from REFERENCE_FUNCTIONAL and sets the associated scaling parameter. [Edit on GitHub]

EPS_CN: real = 1.00000000E-006

  Usage: EPS_CN 1.e-6_dp

  Cutoff value for coordination number function (DFT-D3 method) [Edit on GitHub]

FACTOR_S9_TERM: real = 1.00000000E+000

  Usage: FACTOR_S9_TERM 1.e-0

  S9 prefactor of the many-body term in the DFT-D4 method. [Edit on GitHub]

KIND_COORDINATION_NUMBERS: string[ ]

  Keyword can be repeated.

  Usage: KIND_COORDINATION_NUMBERS CN kind

  Specifies the coordination number for a kind for the C9 term in DFT-D3. [Edit on GitHub]

LONG_RANGE_CORRECTION: logical = F

  Lone keyword: `T`

  Usage: LONG_RANGE_CORRECTION

  Calculate a long range correction to the DFT-D3 model. WARNING: Use with care! Only for isotropic dense systems. [Edit on GitHub]

MOLECULE_CORRECTION: logical = F

  Lone keyword: `T`

  Usage: MOLECULE_CORRECTION

  Calculate a intermolecular correction to the DFT-D3 model [Edit on GitHub]

MOLECULE_CORRECTION_C8: real = 0.00000000E+000

  Usage: MOLECULE_CORRECTION_C8 1.0

  Calculate a intermolecular correction to the C8 term in the DFT-D3 model [Edit on GitHub]

PARAMETER_FILE_NAME: string = dftd3.dat

  Usage: PARAMETER_FILE_NAME <FILENAME>

  Name of the parameter file, may include a path (not used for D4) [Edit on GitHub]

REFERENCE_C9_TERM: logical = F

  Lone keyword: `T`

  Usage: REFERENCE_C9_TERM

  Calculate C9 terms in DFT-D3 model using reference coordination numbers [Edit on GitHub]

REFERENCE_FUNCTIONAL: string

  Usage: REFERENCE_FUNCTIONAL <functional>

  Use parameters for this specific density functional. For available D3 and D3(BJ) parameters see: https://www.chemie.uni-bonn.de/grimme/de/software/dft-d3. For the defintion of D4 parameters see: https://github.com/dftd4/dftd4. [Edit on GitHub]

R_CUTOFF: real = 1.05835442E+001 [angstrom]

  Aliases: D3_CUTOFF ,D4_3B_CUTOFF

  Usage: R_CUTOFF 20.0

  Range of potential. The cutoff will be 2 times this value. In the case of D4 it will be used for the 3-body term [Edit on GitHub]

SHORT_RANGE_CORRECTION: logical = F

  Lone keyword: `T`

  Usage: SHORT_RANGE_CORRECTION

  Calculate a short-range bond correction to the DFT-D3 model [Edit on GitHub]

SHORT_RANGE_CORRECTION_PARAMETERS: real[4] = 8.00000000E-002 1.00000000E+001 5.00000000E-001 -1.00000000E+000

  Usage: SHORT_RANGE_CORRECTION_PARAMETERS

  Parameters for the short-range bond correction to the DFT-D3 model. s*(zazb)^t1EXP(-gdrr0ab^t2), parameters: s, g, t1, t2 Defaults: s=0.08, g=10.0, t1=0.5, t2=-1.0 [Edit on GitHub]

TYPE: enum = DFTD3

  Usage: TYPE (DFTD2|DFTD3|DFTD3(BJ)|DFTD4)

  Valid values:

  - `DFTD2` Grimme D2 method

  - `DFTD3` Grimme D3 method (zero damping)

  - `DFTD3(BJ)` Grimme D3 method (Becke-Johnson damping)

  - `DFTD4` Grimme D4 method

  References: Grimme2006, Grimme2010, Grimme2011, Caldeweyher2020

  Type of potential [Edit on GitHub]

VERBOSE_OUTPUT: logical = F

  Lone keyword: `T`

  Usage: VERBOSE_OUTPUT

  Extensive output for the DFT-D2 and DFT-D3 models. Needs PRINT_DFTD section to be specified. [Edit on GitHub]