# DIELECTRIC

Parameters for the dielectric constant function. [Edit on GitHub]

Subsections

- DIELEC_AA_CUBOIDAL
- DIELEC_XAA_ANNULAR

## Keywords

- DERIVATIVE_METHOD

- DIELECTRIC_CONSTANT

- DIELECTRIC_CORE_CORRECTION

- DIELECTRIC_FUNCTION_TYPE

- RHO_MAX

- RHO_MIN

## Keyword descriptions

DERIVATIVE_METHOD: enum = CD7

  Usage: DERIVATIVE_METHOD <method>

  Valid values:

  - `FFT` FFT based deriv of epsilon, without correction (high cutoff needed).

  - `FFT_USE_DEPS` FFT based deriv of epsilon, with correction using gradient of epsilon (high cutoff needed).

  - `FFT_USE_DRHO` FFT based deriv of epsilon, with correction using gradient of rho (high cutoff needed).

  - `CD3` 3-point central difference derivative.

  - `CD5` 5-point central difference derivative.

  - `CD7` 7-point central difference derivative (recommended).

  Preferred method for evaluating the gradient of ln(eps). [Edit on GitHub]

DIELECTRIC_CONSTANT: real = 8.00000000E+001

  Aliases: EPSILON

  Usage: dielectric_constant <real>

  Dielectric constant in the bulk of the solvent. [Edit on GitHub]

DIELECTRIC_CORE_CORRECTION: logical = T

  Lone keyword: `T`

  Usage: DIELECTRIC_CORE_CORRECTION <logical>

  Avoid spurious values of the dielectric constant at the ionic core for pseudopotentials where the electron density goes to zero at the core (e.g. GTH). The correction is based on rho_core. [Edit on GitHub]

DIELECTRIC_FUNCTION_TYPE: enum = DENSITY_DEPENDENT

  Usage: DIELECTRIC_FUNCTION_TYPE <method>

  Valid values:

  - `DENSITY_DEPENDENT` Dielectric constant as a function of the electron density as e.g. proposed within the SCCS model.

  - `SPATIALLY_DEPENDENT` Various regions with different dielectric constants.

  - `SPATIALLY_RHO_DEPENDENT` Various regions with different dielectric constants. The dielectric constant decays to 1.0, wherever the electron density is present.

  Preferred type for the dielectric constant function. [Edit on GitHub]

RHO_MAX: real = 1.00000000E-003

  Usage: rho_max <real>

  Upper density threshold. [Edit on GitHub]

RHO_MIN: real = 1.00000000E-004

  Usage: rho_min <real>

  Lower density threshold. [Edit on GitHub]