# EFIELD

Section can be repeated.

Parameters for finite, time dependent electric fields. For time dependent propagation in periodic systems, set DFT%REAL_TIME_PROPAGATION%VELOCITY_GAUGE to true. For static fields use EXTERNAL_POTENTIAL. [Edit on GitHub]

Subsections

- CONSTANT_ENV
- CUSTOM_ENV
- GAUSSIAN_ENV
- RAMP_ENV

## Keywords

- ENVELOP

- INTENSITY

- PHASE

- POLARISATION

- VEC_POT_INITIAL

- WAVELENGTH

## Keyword descriptions

ENVELOP: enum = CONSTANT

  Usage: ENVELOP CONSTANT

  Valid values:

  - `CONSTANT` No envelop function is applied to the strength

  - `GAUSSIAN` A Gaussian function is used as envelop

  - `RAMP` Linear tune in/out of the field

  - `CUSTOM` A custom field read from a file

  Shape of the efield pulse used in real-time propagation (RTP) calculations. [Edit on GitHub]

INTENSITY: real = 0.00000000E+000

  Usage: INTENSITY 0.001

  Intensity of the electric field. For real-time propagation (RTP) units are in Wcm-2 which corresponds to a maximal amplitude in a.u. of sqrt(I/(3.5094410^16)). For a constant local field in isolated system calclulations, units are in a.u.. [Edit on GitHub]

PHASE: real = 0.00000000E+000

  Usage: Phase 1.E0

  Phase offset of the cosine given in multiples of pi. Used in real-time propagation (RTP) calculations. [Edit on GitHub]

POLARISATION: real[3] = 0.00000000E+000 0.00000000E+000 1.00000000E+000

  Usage: POLARISATION 0.0 0.0 1.0

  Polarisation vector of electric field [Edit on GitHub]

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

  Usage: vec_pot_initial 1.0E-2 0.0 0.0

  Initial value of the vector potential (for velocity gauge). This input is made especially for restarting RTP calculation. Unit is atomic unit. Note that if several field sections are defined, only the first one will be used. [Edit on GitHub]

WAVELENGTH: real = 0.00000000E+000 [nm]

  Usage: Wavelength 1.E0

  Wavelength of efield field for real-time propagation (RTP) calculations. [Edit on GitHub]