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Manuscript Title: STRFLO: a program for time-independent calculations of multiphoton processes in one-electron atomic systems. I. Quasienergy spectra and angular distributions.
Authors: R.M. Potvliege
Program title: STRFLO
Catalogue identifier: ADIY_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 114(1998)42
Programming language: Fortran.
Computer: SGI Origin 2000.
Operating system: UNIX(AIX 3.2.5/SunOS 5.5.1/DEC OSF1 4.0/IRIX6.4).
RAM: 11M words
Keywords: Floquet, Multiphoton ionization, Ati, Stark effect, Sturmian functions, Complex dilation, Laser physics, Atomic physics, Scattering, Photon.
Classification: 2.5, 15.

Nature of problem:
The dynamics of multiphoton processes in atoms irradiated by an intense laser pulse depends on the underlying spectrum of complex quasienergies, which the program can calculate for hydrogenic systems and for one-electron models. The calculation also yields a wave function describing the decaying atom; it can be used for computing multiphoton ionization rates differential in the energy and in the angle of ejection of the photoelectron.

Solution method:
The Floquet ansatz is made, assuming that the incident field is stationary. This makes it possible to reduce the time-dependent Schrodinger equation to a set of coupled time-independent differential equations. The latter are tackled by imposing Siegert boundary conditions on the wave function, expanding it on a complex basis set, projecting the equations on the basis functions and solving the resulting non-Hermitian matrix eigenvalue problem.

Restrictions:
Relevant restrictions on the intensity and polarization of the fields and on the binding potential are described in the long write-up.

Running time:
15 s for the test data, on a SGI Origin 2000 machine (R10000 processor running at 195 MHz).