STRFLO: A program for time-independent calculations of multiphoton processes in one-electron atomic systems I. Quasienergy spectra and angular distributions Original Research Article

The program presented calculates quasienergy spectra of one-electron atoms or ions undergoing multiphoton ionization in an intense two-colour field or ionization in a strong static electric field. The electron is initially bound by a single Coulomb potential or by a superposition of a short-range potential and a Coulomb potential. Besides quasienergies, the program can obtain rates of photoionization in specific ATI channels and angular distributions of photoelectrons, in the approximation where the atom is represented by a single dressed state. The calculation can be perturbative or nonperturbative. The Floquet equations are solved on a basis of spherical harmonies and complex Sturmian functions.