# TDOutput

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#### TDOutput

Section Time-Dependent::TD Output
Type block
Default multipoles + energy (+ others depending on other options)

Defines what should be output during the time-dependent simulation. Many of the options can increase the computational cost of the simulation, so only use the ones that you need. In most cases the default value is enough, as it is adapted to the details of the TD run. If the ions are allowed to be moved, additionally the geometry and the temperature are output. If a laser is included it will output by default.

Note: the output files generated by this option are updated every RestartWriteInterval steps.

Example:

%TDOutput
multipoles
energy
%

Options:

• multipoles:
Outputs the (electric) multipole moments of the density to the file td.general/multipoles. This is required to, e.g., calculate optical absorption spectra of finite systems. The maximum value of $l$ can be set with the variable TDMultipoleLmax.
• angular:
Outputs the orbital angular momentum of the system to td.general/angular, which can be used to calculate circular dichroism.
• spin:
(Experimental) Outputs the expectation value of the spin, which can be used to calculate magnetic circular dichroism.
• populations:
(Experimental) Outputs the projection of the time-dependent Kohn-Sham Slater determinant onto the ground state (or approximations to the excited states) to the file td.general/populations. Note that the calculation of populations is expensive in memory and computer time, so it should only be used if it is really needed. See TDExcitedStatesToProject.
• geometry:
If set (and if the atoms are allowed to move), outputs the coordinates, velocities, and forces of the atoms to the the file td.general/coordinates. On by default if MoveIons = yes.
• dipole_acceleration:
When set, outputs the acceleration of the electronic dipole, calculated from the Ehrenfest theorem, in the file td.general/acceleration. This file can then be processed by the utility oct-harmonic-spectrum in order to obtain the harmonic spectrum.
• laser:
If set, outputs the laser field to the file td.general/laser. On by default if TDExternalFields is set.
• energy:
If set, octopus outputs the different components of the energy to the file td.general/energy. Will be zero except for every TDEnergyUpdateIter iterations.
• td_occup:
(Experimental) If set, outputs the projections of the time-dependent Kohn-Sham wavefunctions onto the static (zero-time) wavefunctions to the file td.general/projections.XXX. Only use this option if you really need it, as it might be computationally expensive. See TDProjStateStart. The output interval of this quantity is controled by the variable TDOutputComputeInterval In case of states parallelization, all the ground-state states are stored by each task.
• local_mag_moments:
If set, outputs the local magnetic moments, integrated in sphere centered around each atom. The radius of the sphere can be set with LocalMagneticMomentsSphereRadius.
• gauge_field:
If set, outputs the vector gauge field corresponding to a spatially uniform (but time-dependent) external electrical potential. This is only useful in a time-dependent periodic run. On by default if GaugeVectorField is set.
• temperature:
If set, the ionic temperature at each step is printed. On by default if MoveIons = yes.
• ftchd:
Write Fourier transform of the electron density to the file ftchd.X, where X depends on the kick (e.g. with sin-shaped perturbation X=sin). This is needed for calculating the dynamic structure factor. In the case that the kick mode is qbessel, the written quantity is integral over density, multiplied by spherical Bessel function times real spherical harmonic. On by default if TDMomentumTransfer is set.
• dipole_velocity:
When set, outputs the dipole velocity, calculated from the Ehrenfest theorem, in the file td.general/velocity. This file can then be processed by the utility oct-harmonic-spectrum in order to obtain the harmonic spectrum.
• eigenvalues:
Write the KS eigenvalues.
• ionization_channels:
Write the multiple-ionization channels using the KS orbital densities as proposed in C. Ullrich, Journal of Molecular Structure: THEOCHEM 501, 315 (2000).
• total_current:
Output the total current (average of the current density over the cell).
• partial_charges:
Bader and Hirshfeld partial charges. The output file is called 'td.general/partial_charges'.
• td_kpoint_occup:
Project propagated Kohn-Sham states to the states at t=0 given in the directory restart_proj (see %RestartOptions). This is an alternative to the option td_occup, with a formating more suitable for k-points and works only in k- and/or state parallelization
• td_floquet:
Compute non-interacting Floquet bandstructure according to further options: TDFloquetFrequency, TDFloquetSample, TDFloquetDimension. This is done only once per td-run at t=0. works only in k- and/or state parallelization
• n_excited_el:
Output the number of excited electrons, based on the projections of the time evolved wave-functions on the ground-state wave-functions. The output interval of this quantity is controled by the variable TDOutputComputeInterval
• coordinates_sep:
Writes geometries in a separate file.
• velocities_sep:
Writes velocities in a separate file.
• forces_sep:
Writes forces in a separate file.
• total_heat_current:
Output the total heat current (average of the heat current density over the cell).
• total_magnetization:
Writes the total magnetization, where the total magnetization is calculated at the momentum defined by TDMomentumTransfer. This is used to extract the magnon frequency in case of a magnon kick.
• photons_q:
Writes photons_q in a separate file.

Source information

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