High-intensity photoionization of H2
Abstract
A tunable, high intensity picosecond dye laser system has been employed with electron energy analysis to investigate the dynamics of (3+1) resonance-enhanced multiphoton ionization of H2 via different vibrational levels of its B sup 1 Sigma sub u sup + and C sup 1 Pi sub u electronic states. We observe production of molecular ions in various vibrational levels, with a shift to increased population of lower vibrational states of H2(+) consistent with the a.c. Stark shift of the correspondingly lower vibrational levels of the C state into resonance with the three photon energy of the laser. Clear evidence of direct dissociation of H2 followed by single photon ionization of the excited H atom is observed as well. Above threshold ionization of these two processes occurs readily. We also find that dissociative ionization is an increasingly important ionization pathway as the wavelength is increased. Finally, we see evidence of a new ionization pathway, which we assign to photoionization into a transient bound state created by the avoided crossing of the first repulsive electronic state of H2(+), with the single photon dressed ground state of H2(+).
- Publication:
-
Presented at the Conference on Short-Wavelength Coherent Radiation: Generation and Application
- Pub Date:
- May 1991
- Bibcode:
- 1991swcr.confQ...4A
- Keywords:
-
- Dye Lasers;
- Energy Levels;
- Hydrogen;
- Multiphoton Absorption;
- Photoionization;
- Dissociation;
- Electromagnetic Coupling;
- Electron Energy;
- Molecular Energy Levels;
- Atomic and Molecular Physics