H{sub 2} and D{sub 2} in intense sub-picosecond laser pulses: Photoelectron spectroscopy at 1053 and 527 nm

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.54.2224· OSTI ID:383149

Rottke, H; Ludwig, J; Sandner, W ^[1]

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1. Max-Born Institut, Rudower Chaussee 6, P. O. Box 1107, D-12474 Berlin (Germany)

We report multiphoton ionization experiments on H{sub 2} and D{sub 2} molecules at 1053- and 526.5-nm excitation wavelengths in the intensity range 5{times}10{sup 13}{endash}5{times}10{sup 14} W/cm{sup 2}. The intensity dependence of the total ion yield, the dissociation fraction, and the photoelectron spectrum is investigated. At 1053 nm we find a strong isotope effect in the dissociation fraction, whereas at 526.5 nm no such effect is observed. Up to 1{times}10{sup 14} W/cm{sup 2} the photoelectron spectrum at 526.5 nm is dominated by resonant ionization processes via Rydberg states of the molecules. They are shifted into resonance at intensities above {approximately}10{sup 13} W/cm{sup 2}. The spectra show that the potential energy curves of the resonant states must have a shape very similar to the corresponding ionic ones. They are therefore mainly determined by the dipole coupling between the ion core orbitals 1{ital s}{sigma}{sub {ital g}} and 2{ital p}{sigma}{sub {ital u}}. At 1053 nm two photoionization regimes are observed: the multiphoton regime with Keldysh parameter {gamma}{gt}1 showing resonance ionization structures, and the tunnel regime ({gamma}{lt}1) at high intensity. The isotope effect in the dissociation fraction at 1053 nm has no influence on the shape of the corresponding photoelectron spectra at this wavelength. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 383149
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 3 Vol. 54; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
DEUTERIUM
DEUTERIUM MOLECULES
DISSOCIATION
HYDROGEN
HYDROGEN ISOTOPES
HYDROGEN MOLECULES
ISOTOPE EFFECTS
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
RYDBERG STATES