Dissociative ionization of H{sub 2}{sup +} in an intense laser field: Charge-resonance-enhanced ionization, Coulomb explosion, and harmonic generation at 600 nm
- Laboratoire de Chimie Theorique, Faculte des Sciences, Universite de Sherbrooke, Sherbrooke, Quebec, J1K2R1 (CANADA)
The time-dependent Schr{umlt o}dinger equation for H{sub 2}{sup +} in a 600-nm, intense ({ital I}{ge}10{sup 14} W/cm{sup 2}) laser field is solved numerically for a model which uses the exact three-body Hamiltonian with one-dimensional nuclear motion restricted to the direction of the laser electric field and three-dimensional electronic motion. High ionization rates of H{sub 2}{sup +} are found, exceeding those of neutral atomic hydrogen. This confirms, by the rigorous, full dynamical calculation, the recently discovered charge-resonance-enhanced ionization (CREI){emdash}all previous demonstrations of CREI were based on the {open_quote}{open_quote}frozen nuclei{close_quote}{close_quote} model. The numerical kinetic-energy spectra of dissociating fragments are compared with recent experimental results. They can be interpreted by a simple bond softening mechanism (or laser-induced avoided crossing in a dressed-state representation), in which the binding forces are completely suppressed by the strong electric field and thus the dissociating fragments move as free particles with a kinetic energy close to their initial vibrational energy until they reach a critical distance {ital R}={ital R}{sub {ital c}}{congruent}8 bohr, where they are rapidly ionized, due to CREI. The harmonic generation spectra calculated from our non-Born-Oppenheimer simulations show that the high harmonics are also generated when the nuclei cross this critical distance {ital R}={ital R}{sub {ital c}}. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 385697
- Journal Information:
- Physical Review A, Vol. 54, Issue 4; Other Information: PBD: Oct 1996
- Country of Publication:
- United States
- Language:
- English
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