# OPT_EMBED

This section specifies optional parameters for DFT embedding potential optimization. [Edit on GitHub]

Subsections

- EMBED_DENS_DIFF
- EMBED_POT_CUBE
- EMBED_POT_VECTOR
- WRITE_SIMPLE_GRID

## Keywords

- CHARGE_DISTR_WIDTH

- DENS_CONV_INT

- DENS_CONV_MAX

- EMBED_CUBE_FILE_NAME

- EMBED_RESTART_FILE_NAME

- EMBED_SPIN_CUBE_FILE_NAME

- FAB

- GRID_OPT

- LEEUWEN-BAERENDS

- N_ITER

- OPTIMIZER

- POT_GUESS

- READ_EMBED_POT

- READ_EMBED_POT_CUBE

- REG_LAMBDA

- SPIN_DENS_CONV_INT

- SPIN_DENS_CONV_MAX

- TRUST_RAD

- VW_CUTOFF

- VW_SMOOTH_CUT_RANGE

## Keyword descriptions

CHARGE_DISTR_WIDTH: real = 1.12490000E+000

  Usage: CHARGE_DISTR_WIDTH 3.000

  Width of the Gaussian representing point charges. To be used with ADD_COULOMB_POT. [Edit on GitHub]

DENS_CONV_INT: real = 1.00000000E-001

  Usage: DENS_CONV_INT 0.1

  Convergence criterion for the integrated electron density difference. [Edit on GitHub]

DENS_CONV_MAX: real = 1.00000000E-002

  Usage: DENS_CONV_MAX 0.01

  Convergence criterion for the maximum electron density difference. [Edit on GitHub]

EMBED_CUBE_FILE_NAME: string

  Usage: EMBED_CUBE_FILE_NAME <FILENAME>

  Root of the file name where to read the embedding potential (guess) as a cube. [Edit on GitHub]

EMBED_RESTART_FILE_NAME: string

  Usage: EMBED_RESTART_FILE_NAME <FILENAME>

  Root of the file name where to read the embedding potential guess. [Edit on GitHub]

EMBED_SPIN_CUBE_FILE_NAME: string

  Usage: EMBED_SPIN_CUBE_FILE_NAME <FILENAME>

  Root of the file name where to read the spin part of the embedding potential (guess) as a cube. [Edit on GitHub]

FAB: logical = F

  Usage: FAB .TRUE.

  Finzel-Ayers-Bultinck iterative update. Generally, not reliable. [Edit on GitHub]

GRID_OPT: logical = T

  Usage: GRID_OPT .TRUE.

  Optimize embedding potential on the grid. [Edit on GitHub]

LEEUWEN_BAERENDS: logical = F

  Usage: LEEUWEN-BAERENDS .TRUE.

  Van Leeuwen-Baerends iterative update. Alternative to Wu-Yang optimizer. Use only with ADD_CONTST_POT. [Edit on GitHub]

N_ITER: integer = 50

  Usage: N_ITER 75

  Maximum number of iterations in the optimization procedure. [Edit on GitHub]

OPTIMIZER: enum = STEEPEST_DESCENT

  Usage: OPTIMIZER LEVEL_SHIFT

  Valid values:

  - `STEEPEST_DESCENT` Steepest descent.

  - `QUASI_NEWTON` Quasi-Newton.

  - `LEVEL_SHIFT` Level shift.

  Optimize embedding potential. [Edit on GitHub]

POT_GUESS: enum = NONE

  Usage: POT_GUESS NONE

  Valid values:

  - `NONE` Initial guess is zero grid.

  - `DIFF` Initial density difference. A euristic but working approach.

  - `FERMI_AMALDI` Fermi-Amaldi potential. More rigorous than DIFF, although less efficient.

  - `RESP` Coulomb interaction between the subsystem using RESP charges) on the total system.

  Specifies the guess of the embedding potential. For optimization in finite basis (not grid optimization) in is a constant part to be added to the one in finite basis. [Edit on GitHub]

READ_EMBED_POT: logical = F

  Usage: READ_EMBED_POT .FALSE.

  Read the embedding potential restart vector as a guess. [Edit on GitHub]

READ_EMBED_POT_CUBE: logical = F

  Usage: READ_EMBED_POT_CUBE .FALSE.

  Read the embedding potential (restart) from the cube file. [Edit on GitHub]

REG_LAMBDA: real = 1.00000000E-004

  Usage: REG_LAMBDA 0.0001

  Parameter for Yang’s regularization involving kinetic matrix. [Edit on GitHub]

SPIN_DENS_CONV_INT: real = 1.00000000E-001

  Usage: SPIN_DENS_CONV_INT 0.1

  Convergence criterion for the integrated electron density difference. [Edit on GitHub]

SPIN_DENS_CONV_MAX: real = 1.00000000E-002

  Usage: SPIN_DENS_CONV_MAX 0.01

  Convergence criterion for the maximum electron density difference. [Edit on GitHub]

TRUST_RAD: real = 5.00000000E-001

  Usage: TRUST_RAD 0.5

  Maximum number of iterations in the optimization procedure. [Edit on GitHub]

VW_CUTOFF: real = 1.00000000E-002

  Usage: VW_CUTOFF 0.01

  Cutoff for von Weizsacker potential in the FAB optimization procedure. [Edit on GitHub]

VW_SMOOTH_CUT_RANGE: real = 1.00000000E+000

  Usage: VW_SMOOTH_CUT_RANGE 1.0

  Smooth cutoff range for von Weizsacker potential in the FAB optimization procedure. [Edit on GitHub]