Photoionization of helium atoms irradiated with intense vacuum ultraviolet free-electron laser light. Part II. Theoretical modeling of multi-photon and single-photon processes
- LNLS, P.O. Box 6192, CEP 13084-971 Campinas SP (Brazil)
- Germany
- HASYLAB at DESY, D-22603 Hamburg (Germany)
We consider the problem of a helium atom under the radiation field of the DESY vacuum ultraviolet (VUV) free electron laser (FEL) (Phase I ({Dirac_h}/2{pi}) congruent with 13 eV). We find by solving numerically the time-dependent Schroedinger equation, that there is a large probability for resonant two-photon excitation from the ground state into a low kinetic energy state just above the first He ionization threshold. From this it is possible to go into another quasi-free state higher up, by resonant absorption of an additional photon. There is no double ionization of He. These results are in general agreement with the He photoelectron and time-of-flight (TOF) spectra recorded on March 2002, in the last week of the DESY VUV FEL Phase I operation. A detailed report on the experiments is given in a companion paper.
- OSTI ID:
- 20718166
- Journal Information:
- Physical Review. A, Vol. 72, Issue 2; Other Information: DOI: 10.1103/PhysRevA.72.023410; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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Reply to 'Comment on 'Photoionization of helium atoms irradiated with intense vacuum ultraviolet free-electron laser light. Part I. Experimental study of multiphoton and single-photon processes''
Reply to 'Comment on 'Photoionization of helium atoms irradiated with intense vacuum ultraviolet free-electron laser light. Part II. Theoretical modeling of multiphoton and single-photon processes''
Related Subjects
ABSORPTION
ATOMS
DESY
EV RANGE
EXCITATION
FAR ULTRAVIOLET RADIATION
FREE ELECTRON LASERS
GROUND STATES
HELIUM
IRRADIATION
KINETIC ENERGY
LASER RADIATION
MULTI-PHOTON PROCESSES
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
PHOTON-ATOM COLLISIONS
PHOTONS
PROBABILITY
SCHROEDINGER EQUATION
SIMULATION
TIME DEPENDENCE
TIME-OF-FLIGHT METHOD
VISIBLE RADIATION