Multiphoton ionization of hydrogen by an intense 248-nm linearly polarized field

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Physical Review, A; (USA)

DOI:https://doi.org/10.1103/PhysRevA.43.439· OSTI ID:6153756

Pindzola, M S ^[1]; Doerr, M ^[2]

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1. Department of Physics, Auburn University, Auburn, Alabama 36849-5311 (USA)
2. Department of Physics, University of Southern California, Los Angeles, California 90089-0484 (USA)

We study multiphoton ionization of hydrogen by a linearly polarized 248-nm field (the photons have an energy of 5.0 eV) up to an intensity of 10{sup 15} W/cm{sup 2}. We compare two very different computational methods for the calculation of the total ionization rate: on the one hand, the full numerical solution of the time-dependent Schroedinger equation; on the other hand, results obtained within the Floquet formalism, which assumes a quasiperiodic time dependence. We obtain very good agreement between the two sets of calculations throughout the whole intensity range. The calculated rates also agree well with third-order perturbation theory up to 10{sup 13} W/cm{sup 2}, but are orders of magnitude lower at 10{sup 15} W/cm{sup 2}. The shortfall at high intensities is attributed to the change from a nonresonant third-order process to a resonant fourth-order process caused by ac Stark-induced shifts in the energy-level structure of hydrogen. In fact, the ionization rate between 2 and 6{times}10{sup 14} W/cm{sup 2} is almost constant, giving rise to a plateau feature in the rate versus intensity curve.

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6153756
• Journal Information: Physical Review, A; (USA), Vol. 43:1; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
HYDROGEN
PHOTOIONIZATION
ATOMS
CORRELATIONS
CROSS SECTIONS
FLOQUET FUNCTION
FLUX DENSITY
MULTI-PHOTON PROCESSES
POLARIZED BEAMS
SCHROEDINGER EQUATION
STARK EFFECT
ULTRAVIOLET RADIATION
BEAMS
DIFFERENTIAL EQUATIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
EQUATIONS
FUNCTIONS
IONIZATION
NONMETALS
PARTIAL DIFFERENTIAL EQUATIONS
RADIATIONS
WAVE EQUATIONS
640302* - Atomic
Molecular & Chemical Physics- Atomic & Molecular Properties & Theory