PhotoElectronSpectrum

Name PES_Flux_AnisotropyCorrection
Section Time-Dependent::PhotoElectronSpectrum
Type logical

Apply anisotropy correction.

Name PES_Flux_ARPES_grid
Section Time-Dependent::PhotoElectronSpectrum
Type logical

Use a curvilinear momentum space grid that compensates the transformation used to obtain ARPES. With this choice ARPES data is laid out on a Cartesian regular grid. By default true when PES_Flux_Shape = pln and a KPointsPath is specified.

Name PES_Flux_DeltaK
Section Time-Dependent::PhotoElectronSpectrum
Type float
Default 0.02

Spacing of the the photoelectron momentum grid.

Name PES_Flux_EnergyGrid
Section Time-Dependent::PhotoElectronSpectrum
Type block

The block PES_Flux_EnergyGrid specifies the energy grid in momentum space.
%PES_Flux_EnergyGrid
   Emin | Emax | DeltaE
%

Name PES_Flux_Face_Dens
Section Time-Dependent::PhotoElectronSpectrum
Type block

Define the number of points density per unit of area (in au) on the face of the ‘cub’ surface.

Name PES_Flux_GridTransformMatrix
Section Time-Dependent::PhotoElectronSpectrum
Type block

Define an optional transformation matrix for the momentum grid.

%PES_Flux_GridTransformMatrix
   M_11 | M_12 | M_13
   M_21 | M_22 | M_23
   M_31 | M_32 | M_33
%

Name PES_Flux_Kmax
Section Time-Dependent::PhotoElectronSpectrum
Type float
Default 1.0

The maximum value of the photoelectron momentum. For cartesian momentum grids one can specify a value different for cartesian direction using a block input.

Name PES_Flux_Kmin
Section Time-Dependent::PhotoElectronSpectrum
Type float
Default 0.0

The minimum value of the photoelectron momentum. For cartesian momentum grids one can specify a value different for cartesian direction using a block input.

Name PES_Flux_Lmax
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default 80

Maximum order of the spherical harmonic to be integrated on an equidistant spherical grid (to be changed to Gauss-Legendre quadrature).

Name PES_Flux_Lsize
Section Time-Dependent::PhotoElectronSpectrum
Type block

For PES_Flux_Shape = cub sets the dimensions along each direction. The syntax is:

%PES_Flux_Lsize
  xsize | ysize | zsize
%

where xsize, ysize, and zsize are with respect to the origin. The surface can be shifted with PES_Flux_Offset. If PES_Flux_Shape = pln, specifies the position of two planes perpendicular to the non-periodic dimension symmetrically placed at PES_Flux_Lsize distance from the origin.

Name PES_Flux_Momenutum_Grid
Section Time-Dependent::PhotoElectronSpectrum
Type integer

Decides how the grid in momentum space is generated.

Options:

• polar:
  The grid is in polar coordinates with the zenith axis is along z. The grid parameters are defined by PES_Flux_Kmax, PES_Flux_DeltaK, PES_Flux_StepsThetaK, PES_Flux_StepsPhiK. This is the default choice for PES_Flux_Shape = sph or cub.
  
• cartesian:
  The grid is in cartesian coordinates with parameters defined by PES_Flux_ARPES_grid, PES_Flux_EnergyGrid. This is the default choice for PES_Flux_Shape = sph or cub.
  

Name PES_Flux_Offset
Section Time-Dependent::PhotoElectronSpectrum
Type block

Shifts the surface for PES_Flux_Shape = cub. The syntax is:

%PES_Flux_Offset
  xshift | yshift | zshift
%

Name PES_Flux_Parallelization
Section Time-Dependent::PhotoElectronSpectrum
Type flag

The parallelization strategy to be used to calculate the PES spectrum using the resources available in the domain parallelization pool. This option is not available without domain parallelization. Parallelization over k-points and states is always enabled when available.

Options:

• pf_none:
  No parallelization.
  
• pf_time:
  Parallelize time integration. This requires to store some quantities over a number of time steps equal to the number of cores available.
  
• pf_momentum:
  Parallelize over the final momentum grid. This strategy has a much lower memory footprint than the one above (time) but seems to provide a smaller speedup.
  
• pf_surface:
  Parallelize over surface points.

  Option pf_time and pf_surface can be combined: pf_time + pf_surface.

  
  

Name PES_Flux_PhiK
Section Time-Dependent::PhotoElectronSpectrum
Type block

Define the grid points on theta ($0 \le \theta \le 2\pi$) when using a spherical grid in momentum. The block defines the maximum and minimum values of theta and the number of of points for the discretization.

%PES_Flux_PhiK
   theta_min | theta_max | npoints
%

By default theta_min=0, theta_max = pi, npoints = 90.

Name PES_Flux_Radius
Section Time-Dependent::PhotoElectronSpectrum
Type float

The radius of the sphere, if PES_Flux_Shape == sph.

Name PES_Flux_RuntimeOutput
Section Time-Dependent::PhotoElectronSpectrum
Type logical

Write output in ascii format at runtime.

Name PES_Flux_Shape
Section Time-Dependent::PhotoElectronSpectrum
Type integer

The shape of the surface.

Options:

• cub:
  Uses a parallelepiped as surface. All surface points are grid points. Choose the location of the surface with variable PES_Flux_Lsize (default for 1D and 2D).
  
• sph:
  Constructs a sphere with radius PES_Flux_Radius. Points on the sphere are interpolated by trilinear interpolation (default for 3D).
  
• pln:
  This option is for periodic systems. Constructs a plane perpendicular to the non-periodic dimension at PES_Flux_Lsize.
  

Name PES_Flux_StepsPhiK
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default 90

Number of steps in $\phi$ ($0 \le \phi \le 2 \pi$) for the spherical grid in k.

Name PES_Flux_StepsPhiR
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default 2 PES_Flux_Lmax + 1

Number of steps in $\phi$ ($0 \le \phi \le 2 \pi$) for the spherical surface.

Name PES_Flux_StepsThetaK
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default 45

Number of steps in $\theta$ ($0 \le \theta \le \pi$) for the spherical grid in k.

Name PES_Flux_StepsThetaR
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default 2 PES_Flux_Lmax + 1

Number of steps in $\theta$ ($0 \le \theta \le \pi$) for the spherical surface.

Name PES_Flux_ThetaK
Section Time-Dependent::PhotoElectronSpectrum
Type block

Define the grid points on theta ($0 \le \theta \le \pi$) when using a spherical grid in momentum. The block defines the maximum and minimum values of theta and the number of of points for the discretization.

%PES_Flux_ThetaK
   theta_min | theta_max | npoints
%

By default theta_min=0, theta_max = pi, npoints = 45.

Name PES_Flux_UseSymmetries
Section Time-Dependent::PhotoElectronSpectrum
Type logical

Use surface and momentum grid symmetries to speed up calculation and lower memory footprint. By default available only when the surface shape matches the grid symmetry i.e.: PES_Flux_Shape = m_cub or m_pln and PES_Flux_Momenutum_Grid = m_cartesian or PES_Flux_Shape = m_sph and PES_Flux_Momenutum_Grid = m_polar

Name PES_spm_DeltaOmega
Section Time-Dependent::PhotoElectronSpectrum
Type float

The spacing in frequency domain for the photoelectron spectrum (if PES_spm_OmegaMax > 0). The default is PES_spm_OmegaMax/500.

Name PES_spm_OmegaMax
Section Time-Dependent::PhotoElectronSpectrum
Type float
Default 0.0

If PES_spm_OmegaMax > 0, the photoelectron spectrum is directly calculated during time-propagation, evaluated by the PES_spm method. PES_spm_OmegaMax is then the maximum frequency (approximate kinetic energy) and PES_spm_DeltaOmega the spacing in frequency domain of the spectrum.

Name PES_spm_points
Section Time-Dependent::PhotoElectronSpectrum
Type block

List of points at which to calculate the photoelectron spectrum by the sample point method. If no points are given, a spherical grid is generated automatically. The exact syntax is:

%PES_spm_points
  x1 | y1 | z1
%

Name PES_spm_Radius
Section Time-Dependent::PhotoElectronSpectrum
Type float

The radius of the sphere for the spherical grid (if no PES_spm_points are given).

Name PES_spm_recipe
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default phase

The type for calculating the photoelectron spectrum in the sample point method.

Options:

• raw:
  Calculate the photoelectron spectrum according to A. Pohl, P.-G. Reinhard, and E. Suraud, Phys. Rev. Lett. 84, 5090 (2000).
  
• phase:
  Calculate the photoelectron spectrum by including the Volkov phase (approximately), see P. M. Dinh, P. Romaniello, P.-G. Reinhard, and E. Suraud, Phys. Rev. A. 87, 032514 (2013).
  

Name PES_spm_StepsPhiR
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default 90

Number of steps in $\phi$ ($0 \le \phi \le 2 \pi$) for the spherical grid (if no PES_spm_points are given).

Name PES_spm_StepsThetaR
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default 45

Number of steps in $\theta$ ($0 \le \theta \le \pi$) for the spherical grid (if no PES_spm_points are given).

Name PESMask2PEnlargeFactor
Section Time-Dependent::PhotoElectronSpectrum
Type float
Default 1.0

Mask two points enlargement factor. Enlarges the mask box by adding two points at the edges of the box in each direction (x,y,z) at a distance L=Lb*PESMask2PEnlargeFactor where Lb is the box size. This allows to run simulations with an additional void space at a price of adding few points. The Fourier space associated with the new box is restricted by the same factor.

Note: needs PESMaskPlaneWaveProjection = nfft_map or pnfft_map .

Name PESMaskEnlargeFactor
Section Time-Dependent::PhotoElectronSpectrum
Type float
Default 1

Mask box enlargement level. Enlarges the mask bounding box by a PESMaskEnlargeFactor. This helps to avoid wavefunction wrapping at the boundaries.

Name PESMaskFilterCutOff
Section Time-Dependent::PhotoElectronSpectrum
Type float
Default -1

In calculation with PESMaskMode = fullmask_mode and NFFT, spurious frequencies may lead to numerical instability of the algorithm. This option gives the possibility to filter out the unwanted components by setting an energy cut-off. If PESMaskFilterCutOff = -1 no filter is applied.

Name PESMaskIncludePsiA
Section Time-Dependent::PhotoElectronSpectrum
Type logical
Default false

Add the contribution of $\Psi_A$ in the mask region to the photo-electron spectrum. Literally adds the Fourier components of: $\Theta(r-R1) \Psi_A(r)$ with $\Theta$ being the Heaviside step function. With this option PES will contain all the contributions starting from the inner radius $R1$. Use this option to improve convergence with respect to the box size and total simulation time. Note: Carefully choose $R1$ in order to avoid contributions from returning electrons.

Name PESMaskMode
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default mask_mode

PES calculation mode.

Options:

• mask_mode:
  Mask method.
  
• fullmask_mode:
  Full mask method. This includes a back action of the momentum-space states on the interaction region. This enables electrons to come back from the continuum.
  
• passive_mode:
  Passive analysis of the wf. Simply analyze the plane-wave components of the wavefunctions on the region r > R1. This mode employs a step masking function by default.
  

Name PESMaskPlaneWaveProjection
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default fft_map

With the mask method, wavefunctions in the continuum are treated as plane waves. This variable sets how to calculate the plane-wave projection in the buffer region. We perform discrete Fourier transforms (DFT) in order to approximate a continuous Fourier transform. The major drawback of this approach is the built-in periodic boundary condition of DFT. Choosing an appropriate plane-wave projection for a given simulation in addition to PESMaskEnlargeFactor and PESMask2PEnlargeFactorwill help to converge the results.

NOTE: depending on the value of PESMaskMode PESMaskPlaneWaveProjection, may affect not only performance but also the time evolution of the density.

Options:

• fft_out:
  FFT filtered in order to keep only outgoing waves. 1D only.
  
• fft_map:
  FFT transform.
  
• nfft_map:
  Non-equispaced FFT map.
  
• pfft_map:
  Use PFFT library.
  
• pnfft_map:
  Use PNFFT library.
  

Name PESMaskShape
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default m_sin2

The mask function shape.

Options:

• m_sin2:
  sin2 mask.
  
• m_step:
  
• m_erf:
  

Name PESMaskSize
Section Time-Dependent::PhotoElectronSpectrum
Type block

Set the size of the mask function. Here you can set the inner (R1) and outer (R2) radius by setting the block as follows:

%PESMaskSize
   R1 | R2 | "user-defined"
%

The optional 3rd column is a user-defined expression for the mask function. For example, r creates a spherical mask (which is the default for BoxShape = sphere). Note, values R2 larger than the box size may lead in this case to unexpected reflection behaviours.

Name PESMaskSpectEnergyMax
Section Time-Dependent::PhotoElectronSpectrum
Type float
Default maxval(mask%Lk)$^2/2$

The maximum energy for the PES spectrum.

Name PESMaskSpectEnergyStep
Section Time-Dependent::PhotoElectronSpectrum
Type float

The PES spectrum energy step.

Name PESMaskStartTime
Section Time-Dependent::PhotoElectronSpectrum
Type float
Default -1.0

The time photoelectrons start to be recorded. In pump-probe simulations, this allows getting rid of an unwanted ionization signal coming from the pump. NOTE: This will enforce the mask boundary conditions for all times.

Name PhotoElectronSpectrum
Section Time-Dependent::PhotoElectronSpectrum
Type integer
Default none

This variable controls the method used for the calculation of the photoelectron spectrum. You can specify more than one value by giving them as a sum, for example: PhotoElectronSpectrum = pes_spm + pes_mask

Options:

• none:
  The photoelectron spectrum is not calculated. This is the default.
  
• pes_spm:
  Store the wavefunctions at specific points in order to calculate the photoelectron spectrum at a point far in the box as proposed in A. Pohl, P.-G. Reinhard, and E. Suraud, Phys. Rev. Lett. 84, 5090 (2000).
  
• pes_mask:
  Calculate the photo-electron spectrum using the mask method. U. De Giovannini, D. Varsano, M. A. L. Marques, H. Appel, E. K. U. Gross, and A. Rubio, Phys. Rev. A 85, 062515 (2012).
  
• pes_flux:
  Calculate the photo-electron spectrum using the t-surff technique, i.e., spectra are computed from the electron flux through a surface close to the absorbing boundaries of the box. (Experimental.) L. Tao and A. Scrinzi, New Journal of Physics 14, 013021 (2012).