Multiquanta photodetachment from the H sup minus ion

Technical Report · Sun Mar 01 04:00:00 EST 1992

OSTI ID:5611639

Tang, Chen-Yau

Multiphoton detachment (MPD) of an electron from the loosely bound H{sup {minus}} system (binding energy = 0.7542 eV) has been studied at various photon energies and laser intensities. In the center of mass of 800-MeV H{sup {minus}} ions the CO{sub 2} laser photon energy, 0.117 eV, was Doppler tuned over a wide range, from 0.15 to 0.39 eV. The peak laser intensity in the lab frame was varied from 2 to 12 GW/cm{sup 2}. The general behavior of MPD versus photon energy and the ac-Stark/pondermotive effects are of special interest in the study. Characteristic threshold structures by absorption of 2, 3, 4, and 5 photons were observed, as evidenced by rapid changes in the signal amplitudes. These thresholds provide a straightforward picture of channel opening in MPD as the photon energy is increased. A fit of two-photon detachment data to the Wigner threshold law showed a good match with a small intensity-induced shift in the threshold energy. A study of laser intensity effects demonstrated departures from the simple power law predicted by lowest-order perturbation theory, which is possibly another indication of pondermotive shifts in the threshold. The absolute MPD rates have been estimated and found to be in fairly good agreement with the results of Floquet theory.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5611639
• Report Number(s): LA-12254T; ON: DE92010306
• Country of Publication: United States
• Language: English

Related Subjects

664400* -- Experimentally Derived Information on Atomic & Molecular Properties-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ANIONS
CARBON DIOXIDE LASERS
CHARGED PARTICLES
CROSS SECTIONS
DATA
ELECTROMAGNETIC RADIATION
ELECTRON DETACHMENT
EQUATIONS
EXPERIMENTAL DATA
FUNCTIONS
GAS LASERS
HYDROGEN IONS
HYDROGEN IONS 1 MINUS
INFORMATION
INTEGRAL EQUATIONS
IONIZATION
IONS
LASER RADIATION
LASERS
MULTI-PHOTON PROCESSES
NUMERICAL DATA
PERTURBATION THEORY
PHOTOIONIZATION
RADIATIONS
WAVE FUNCTIONS