oct-propagate_spectrum - Calculates the absorption cross section tensor from the results of a time-propagation run.
[oct-propagate_spectrum does not read the standard input: all standard input will be simply ignored. An input file named inp must be present in the running directory. Also, oct-propagate_spectrum accepts no command line arguments, since there is not a standard way to do this with Fortran 90.]
This program is one of the Octopus utilities.
This utility generates the dipole strength function of the given system. Its main input is the td.general/multipoles file. Output is written to a file called spectrum. This file is made of two columns: energy (in eV or a.u., depending on the units specified in the input file), and dipole strength function (in 1/eV, or 1/a.u., idem).
In the input file, the user may set the PropagationSpectrumTransform (this should be set to “sine” for proper use), the PropagationSpectrumDampMode (recommended value is “polynomial”, which ensures fulfilling of the N-sum rule), the PropagationSpectrumStartTime, the PropagationSpectrumEndTime, the PropagationSpectrumEnergyStep, and the PropagationSpectrumMaxEnergy.