Resonant multiphoton ionization of H/sub 2/ via the E-italic,F-italic /sup 1/. sigma. /sub g//sup +/ state: Absorption of photons in the ionization continuum
This work reports the five-photon ionization of the H/sub 2/ molecule via the four-photon transitions (E-italic,F-italic /sup 1/..sigma../sub g//sup +/, v-italic/sub E-italic/ = 1,2,3)(X-italic /sup 1/..sigma../sub g//sup +/, v-italic = 0), in the 10/sup 11/-W/cm/sup 2/ laser-intensity range. The resulting H/sup +/- and H/sub 2/ /sup +/-ion spectra exhibit essentially the Q-italic(J-italic) resonances, and the ratio (H/sup +/)/(H/sub 2/ /sup +/) is found to increase drastically with the vibrational quantum number v-italic/sub E-italic/. The photoelectron energy spectra are dominated by the peak corresponding to the five-photon ionization of H/sub 2/ leading to H/sub 2/ /sup +/ ions in the v-italic/sub +/ = v/sub E/ vibrational level. The photodissociation of H/sub 2/ /sup +/ is found to be the only process which forms H/sup +/. In addition, we report: for the first time, to our knowledge: the absorption by a molecule of an extra photon above the ionization potential, when the laser intensity is increased up to 7 x 10/sup 11/ W/cm/sup 2/.
- Research Organization:
- Service de Physique des Atomes et des Surfaces, Commissariat a-grave-accent l'Energie Atomique, Centre d'Etudes Nucle-acute-accentaires de Saclay, 91191 Gif-sur-Yvette Ce-acute-accentdex, France
- OSTI ID:
- 5571779
- Journal Information:
- Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 34:1; ISSN PLRAA
- Country of Publication:
- United States
- Language:
- English
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