# SCCS

References: Fattebert2002, Andreussi2012, Yin2017

Define the parameters for self-consistent continuum solvation (SCCS) model [Edit on GitHub]

Subsections

- ANDREUSSI
- FATTEBERT-GYGI

## Keywords

- SECTION_PARAMETERS

- ALPHA

- BETA

- DELTA_RHO

- DERIVATIVE_METHOD

- EPS_SCCS

- EPS_SCF

- GAMMA

- MAX_ITER

- METHOD

- MIXING

- RELATIVE_PERMITTIVITY

## Keyword descriptions

SECTION_PARAMETERS: logical = F

  Lone keyword: `T`

  Usage: &SCCS ON

  Controls the activation of the SCCS section [Edit on GitHub]

ALPHA: real = 0.00000000E+000 [mN*m^-1]

  Solvent specific tunable parameter for the calculation of the repulsion term \(G^\text{rep} = \alpha S\) where \(S\) is the (quantum) surface of the cavity [Edit on GitHub]

BETA: real = 0.00000000E+000 [GPa]

  Solvent specific tunable parameter for the calculation of the dispersion term \(G^\text{dis} = \beta V\) where \(V\) is the (quantum) volume of the cavity [Edit on GitHub]

DELTA_RHO: real = 2.00000000E-005

  Numerical increment for the calculation of the (quantum) surface of the solute cavity [Edit on GitHub]

DERIVATIVE_METHOD: enum = FFT

  Usage: DERIVATIVE_METHOD cd5

  Valid values:

  - `FFT` Fast Fourier transformation

  - `CD3` 3-point stencil central differences

  - `CD5` 5-point stencil central differences

  - `CD7` 7-point stencil central differences

  Method for the calculation of the numerical derivatives on the real-space grids [Edit on GitHub]

EPS_SCCS: real = 1.00000000E-006

  Aliases: EPS_ITER ,TAU_POL

  Usage: EPS_ITER 1.0E-7

  Tolerance for the convergence of the polarisation density, i.e. requested accuracy for the SCCS iteration cycle [Edit on GitHub]

EPS_SCF: real = 5.00000000E-001

  Usage: EPS_SCF 1.0E-2

  The SCCS iteration cycle is activated only if the SCF iteration cycle is converged to this threshold value [Edit on GitHub]

GAMMA: real = 0.00000000E+000 [mN*m^-1]

  Aliases: SURFACE_TENSION

  Surface tension of the solvent used for the calculation of the cavitation term \(G^\text{cav} = \gamma S\) where \(S\) is the (quantum) surface of the cavity [Edit on GitHub]

MAX_ITER: integer = 100

  Usage: MAX_ITER 50

  Maximum number of SCCS iteration steps performed to converge within the given tolerance [Edit on GitHub]

METHOD: enum = ANDREUSSI

  Usage: METHOD Fattebert-Gygi

  Valid values:

  - `ANDREUSSI` Smoothing function proposed by Andreussi et al.

  - `FATTEBERT-GYGI` Smoothing function proposed by Fattebert and Gygi

  Method used for the smoothing of the dielectric function [Edit on GitHub]

MIXING: real = 6.00000000E-001

  Aliases: ETA

  Usage: MIXING 0.2

  Mixing parameter (Hartree damping) employed during the iteration procedure [Edit on GitHub]

RELATIVE_PERMITTIVITY: real = 8.00000000E+001

  Aliases: DIELECTRIC_CONSTANT ,EPSILON_RELATIVE ,EPSILON_SOLVENT

  Usage: RELATIVE_PERMITTIVITY 78.36

  Relative permittivity (dielectric constant) of the solvent (medium) [Edit on GitHub]