Precision calculation of above-threshold multiphoton ionization in intense short-wavelength laser fields: The momentum-space approach and time-dependent generalized pseudospectral method

Journal Article · Sat Jan 15 00:00:00 EST 2011 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.83.013405· OSTI ID:21529095

Zhongyuan, Zhou ^[1]; Chu, Shih-I ^[1]

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1. Department of Chemistry, University of Kansas, Lawrence, Kansas 66045 (United States)

We present an approach in momentum (P) space for the accurate study of multiphoton and above-threshold ionization (ATI) dynamics of atomic systems driven by intense laser fields. In this approach, the electron wave function is calculated by solving the P-space time-dependent Schroedinger equation (TDSE) in a finite P-space volume under a simple zero asymptotic boundary condition. The P-space TDSE is propagated accurately and efficiently by means of the time-dependent generalized pseudospectral method with optimal momentum grid discretization and a split-operator time propagator in the energy representation. The differential ionization probabilities are calculated directly from the continuum-state wave function obtained by projecting the total electron wave function onto the continuum-state subspace using the projection operator constructed by the continuum eigenfunctions of the unperturbed Hamiltonian. As a case study, we apply this approach to the nonperturbative study of the multiphoton and ATI dynamics of a hydrogen atom exposed to intense short-wavelength laser fields. High-resolution photoelectron energy-angular distribution and ATI spectra have been obtained. We find that with the increase of the laser intensity, the photoelectron energy-angular distribution changes from circular to dumbbell shaped and is squeezed along the laser field direction. We also explore the change of the maximum photoelectron energy with laser intensity and strong-field atomic stabilization phenomenon in detail.

• OSTI ID: 21529095
• Journal Information: Physical Review. A, Vol. 83, Issue 1; Other Information: DOI: 10.1103/PhysRevA.83.013405; (c) 2011 American Institute of Physics; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ACCURACY
ANGULAR DISTRIBUTION
ASYMPTOTIC SOLUTIONS
BOUNDARY CONDITIONS
EIGENFUNCTIONS
ELECTRONS
ENERGY SPECTRA
HAMILTONIANS
HYDROGEN
LASER RADIATION
MATHEMATICAL SPACE
MULTI-PHOTON PROCESSES
PHOTOIONIZATION
PROBABILITY
PROJECTION OPERATORS
SCHROEDINGER EQUATION
SPACE-TIME
STABILIZATION
TIME DEPENDENCE
WAVE FUNCTIONS
WAVELENGTHS
DIFFERENTIAL EQUATIONS
DISTRIBUTION
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ELEMENTS
EQUATIONS
FERMIONS
FUNCTIONS
IONIZATION
LEPTONS
MATHEMATICAL OPERATORS
MATHEMATICAL SOLUTIONS
NONMETALS
PARTIAL DIFFERENTIAL EQUATIONS
QUANTUM OPERATORS
RADIATIONS
SPACE
SPECTRA
WAVE EQUATIONS