field section

The field section defines the parameters of the applied external electric field.

The section is mandatory for any simulation involving a response calculation (static or dynamic).

Valid keywords

Keyword	Type	Allowed Values	Default
type	string	static, dynamic	–
rhs type	string	field, potential	field
field intensity	float	–	1.0e-4 a.u.
nfreq	integer	–	–
min freq	float or string	–	units: eV
max freq	float or string	–	units: eV
step freq	float or string	–	units: eV
external freq	float or string	–	units: eV
polarization	string	none, x, y, z, all	all

Some additional notes on the keywords are given below.

Notes

• type selects the nature of the field:

  • static : static field.

  • dynamic : frequency-dependent field (linear absorption spectra, etc.).

• rhs type determines the formalism exploited for the right-hand side source term of the response equation (they are equivalent):

  • field : electric field vector.

  • potential : scalar potential.

• field intensity sets the amplitude of the external field in atomic units.

• nfreq is number of external frequencies [optional]

• min freq, max freq, step freq define a frequency scan. The user must provide at least 3 between nfreq and these keywords.

• external freq can be used to specify specific custom frequencies instead of a range.

• All frequency values can be provided as either a float (e.g. 3.2 default units: eV) or a string with unit (e.g. 3.2 eV). Allowed units are:

  • eV

  • nm [in this case min freq and max freq are exchanged by plasmonX]

  • micron or um [in this case min freq and max freq are exchanged by plasmonX]

  • cm-1 or cm^-1

  • thz

  • au or a.u.

• polarization defines the direction of the field vector:

  • x, y, z : linear polarization along specific axis

  • all : linear polarization along all axis

  • none : disables polarization (energy calculation)

Example

field:
  type: dynamic
  rhs type: field
  field intensity: 1.0
  min freq: 1.0
  max freq: 5.0
  step freq: 0.05
  polarization: all