Photoion angular distributions in dissociative photoionization of H₂ at 304 Å

Journal Article · Sat Jul 01 00:00:00 EDT 1978 · Physical Review, A (General Physics)

DOI:https://doi.org/10.1103/PhysRevA.18.164· OSTI ID:6667655

Dehmer, Joseph L. ^[1]; Dill, Dan ^[2]

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1. Argonne National Laboratory (ANL), Argonne, IL (United States)
2. Boston Univ., MA (United States). Dept. of Chemistry

Photoionization of H₂ by 304-Å radiation can produce the 2pσ_u, 2pπ_u, and 2sσ_g repulsive states of H₂⁺. The angular distributions of energetic (> 2 eV) protons from these states have been measured relative to the incident unpolarized light beam using a rotatable hemispherical electrostatic analyzer. Axial-recoil conditions apply in this situation, so that the photofragment angular distribution would be sin²θ for pure Σ→Σ electronic transitions and 1 + cos²θ for pure Σ→Π electronic transitions. However, unlike photodissociation processes forming neutral products, the present process also involves the ejection of photoelectrons with alternative symmetries, each associated with one of the above characteristic photoion angular distributions. Consequently, measurement of the net photoion angular distribution in dissociative photoionization yields the branching ratio between the alternative (degenerate) channels available to the photoelectron. This type of information cannot be deduced by observing the photoelectron itself. The present results indicate that the formation of the 2pσ_u state H₂⁺ at 304 Å is accompanied by ejection of photoelectrons with significant d-wave character.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE; Alfred P. Sloan Foundation
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6667655
• Journal Information: Physical Review, A (General Physics), Journal Name: Physical Review, A (General Physics) Journal Issue: 1 Vol. 18; ISSN PLRAAN; ISSN 0556-2791
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
CATIONS
CHARGED PARTICLES
CRYOGENIC FLUIDS
DISSOCIATION
DISTRIBUTION
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
HYDROGEN
HYDROGEN IONS
HYDROGEN IONS 1 PLUS
IONIZATION
IONS
NONMETALS
PHOTOIONIZATION
RADIATIONS
ULTRAVIOLET RADIATION