Photoionization of hydrogen atom by coherent intense high-frequency short laser pulses: Direct propagation of electron wave packets on large spatial grids

Abstract

The time-dependent Schrödinger equation for the hydrogen atom and its interaction with coherent intense high-frequency short laser pulses is solved numerically exactly by propagating the single-electron wave packets. Thereby, the wavefunction is followed in space and time for times longer than the pulse duration. Results are explicitly shown for 3 and 10 fs pulses. Particular attention is paid to identifying the effect of dynamic interference of photoelectrons emitted with the same kinetic energy at different times during the rising and falling sides of the pulse predicted in [\emph{Ph.V. Demekhin and L.S. Cederbaum}, Phys. Rev. Lett. \textbf{108}, 253001 (2012)]. In order to be able to see the dynamic interference pattern in the computed electron spectra, the photoelectron wave packet has to be propagated over long distances. Clearly, complex absorption potentials often employed to compute spectra of emitted particles cannot be used to detect dynamic interference. For the considered high-frequency pulses of 3 and 10 fs durations, this requires enormously large spatial grids. The presently computed photoionization and above-threshold ionization spectra are found to exhibit pronounced dynamic interference patterns. Where available, the patterns are in very good agreement with previously published results on the photoionization spectra which have been computed using a completely different method, thus supporting the previously made assumption that the above-threshold ionization processes are very weak for the considered pulse intensities and high carrier frequency. The quiver motion in space and time of a free electron in strong laser pulses is also investigated numerically. Finally, a discussion is presented of how fast the atom is ionized by an intense pulse.

8 pages, 5 figures

References in corpus (5)

• The multi-configurational time-dependent Hartree method for bosons: Many-body dynamics of bosonic systems
• Strong interference effects in the resonant Auger decay of atoms induced by intense X-Ray fields
• Coherent intense resonant laser pulses lead to interference in the time domain observable in the spectrum of the emitted particles
• Evidence for a {\bf T}-shape break-up pattern in the triple photoionization of Li
• Overcoming blockade in producing doubly-excited dimers by a single intense pulse and their decay

Cited by in corpus (8)

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• Impact of intense laser pulses on the autoionization dynamics of the 2s2p doubly-excited state of He
• Impact of two-electron dynamics and correlations on high-order harmonic generation in He
• Simulation of a Hydrogen Atom in Laser Field Using the Time-Dependent Variational Principle
• Non-adiabatic molecular association in thermal gases driven by radio-frequency pulses