Competition among autoionization, predissociation, and ion-pair formation in molecular hydrogen

Conference · Thu Dec 31 23:00:00 EST 1992

DOI:https://doi.org/10.2172/10126843· OSTI ID:7013590

Dehmer, Joseph L. ^[1]; Dehmer, Patricia M. ^[1]; Pratt, Stephen T. ^[1]; McCormack, E. F. ^[1]

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1. Argonne National Laboratory (ANL), Argonne, IL (United States)

We have investigated autoionization, predissociation, and ion-pair formation highly excited states of molecular hydrogen by using double-resonance excitation via the E,F ¹Σ_g⁺, v=6 level. The energetic threshold for ion-pair formation occurs just below the H₂⁺ X ²Σ_g⁺, v⁺=9 ionization threshold. The spectrum in this region was studied by using conventional and constant-ionic-state photoelectron spectroscopy, by monitoring the H⁻ production, and by detecting dissociation products by ionization with a third laser. The decay dynamics in this region are extremely rich, because the excited levels may decay by rotational and vibrational autoionization, by predissociation to neutral H + H* (n=2,3,4), by predissociation to the ion pair H⁺ + H⁻, and by fluorescence. In addition, the dissociative potential curve of the 2pσ_u3sσ_g ¹Σ_u⁺ doubly excited electronic state crosses the H₂⁺ X ²Σ_g⁺ potential curve in the same energy ion, and the electronic autoionization of this state is found to significantly influence these decay processes.

• Research Organization: Argonne National Lab., IL (United States)
• Sponsoring Organization: USDOE Office of Environment, Health, Safety and Security
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 7013590
• Report Number(s): ANL/ER/CP-78668; CONF-930159--7; ON: DE93006759
• Country of Publication: United States
• Language: English

Related Subjects

664200 -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
664400* -- Experimentally Derived Information on Atomic & Molecular Properties-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
AUTOIONIZATION
CROSS SECTIONS
DATA
DISSOCIATION
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
ELEMENTS
ENERGY LEVELS
EXCITED STATES
EXPERIMENTAL DATA
HYDROGEN
INFORMATION
ION PAIRS
IONIZATION
LASER RADIATION
MOLECULES
MULTI-PHOTON PROCESSES
NONMETALS
NUMERICAL DATA
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
RADIATIONS
RYDBERG STATES
SPECTROSCOPY