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[Licence| Download | New Version Template] adxb_v2_0.tar.gz(84 Kbytes)
Manuscript Title: Photoelectron spectra with Qprop and t-SURFF
Authors: Volker Mosert, Dieter Bauer
Program title: Qprop
Catalogue identifier: ADXB_v2_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 207(2016)452
Programming language: C++.
Computer: x86_64.
Operating system: Linux.
RAM: The memory requirements for calculating PES are determined by the maximum ℓ in the spherical harmonics expansion of the wave function and the number of momentum (or energy) values for which the PES is to be calculated. The example with the largest memory demand (large-clubs) uses approximately 6GB of RAM. The size of the numerical representation of a wavefunction during propagation is modest for the examples included (53 MB for the large-club example).
Number of processors used: The evaluation of the PES can be distributed over up to Nk MPI processes (Nk is the number of momentum values).
Keywords: Photoelectron spectrum, time-dependent surface flux method, strong laser fields, time-dependent Schrödinger equation, spherical harmonics expansion.
Classification: 2.5.

External routines: GNU Scientific Library, Open MPI (optional), BOOST (optional)

Does the new version supersede the previous version?: For TDDFT calculations the previous version should be used.

Nature of problem:
When atoms are ionized by intense laser fields electrons may escape with large momenta (especially when rescattering is involved). This translates to a rapidly spreading wavefunction in numerical simulations of these systems thus rendering the calculation of PES very costly for increasing wave lengths and peak intensities.

Solution method:
The TDSE is solved by propagating the wavefunction using a Crank-Nicolson propagator. The wavefunction is represented by an expansion in spherical harmonics. In order to reduce the requirements with respect to the grid size the t-SURFF method is used to calculate PES.

Reasons for new version:
Using the window operator method to calculate PES is increasingly costly with increasing ponderomotive energies and pulse durations. The new version of Qprop provides an implementation of the t-SURFF method which allows the use of much smaller numerical grids.

Summary of revisions:
An implementation of the t-SURFF method and examples for calculating PES are provided in the new release.

Restrictions:
The dipole approximation for the laser interaction has to be applicable. t-SURFF is only implemented for velocity gauge. Furthermore a finite cutoff for long range binding potentials has to be used in the implemented t-SURFF method.

Additional comments:
For additional information see www.qprop.de

Running time:
Depends strongly on the laser interaction studied. The examples given in this paper have run times from a few minutes to 12.5 hours.