Shape-resonance-enhanced continuum–continuum coupling in photoionization of CO₂

Journal Article · Fri Jan 01 04:00:00 EST 1993 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.465324· OSTI ID:6425522

Siggel, M. R. F. ^[1]; West, J. B. ^[1]; Hayes, M. A. ^[1]; Parr, Albert C. ^[2]; Dehmer, Joseph L. ^[3]; Iga, I. ^[4]

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1. Daresbury Lab, Daresbury, Warrington, (United Kingdom).
2. National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States)
3. Argonne National Lab. (ANL), Argonne, IL (United States)
4. Dpartamento de Quimica, Universidade Federal de Sao Carlos, (Brazil)

We have measured photoionization branching ratios and photoelectron asymmetry parameters for photoionization of CO₂ leading to the first four electronic states of CO₂⁺ over the photon energy range from 20 to 50 eV. The motivation for this work was the prediction by Lucchese [J. Chem. Phys. 92, 4203 (1990)] that the σ_u shape resonance in the (4σ_g)⁻¹ C²Σ⁺_g ionization channel would influence the photoionization dynamics in the other valence-shell continua through continuum--continuum channel interaction, with the main effect occurring in the (3σ_u)⁻¹ B²Σ⁺_u channel. Indeed, clear evidence for this phenomenon is observed in this channel, the most prominent indication being a broad, shallow minimum in the asymmetry parameter at ~40 eV. Comparisons of the present results with theory and other measurements reflect good overall agreement and provide some guidance regarding the effectiveness of alternative approximations used in the theoretical calculations.

• Research Organization: Daresbury Lab, Daresbury, Warrington, (United Kingdom); National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Dpartamento de Quimica, Universidade Federal de Sao Carlos, (Brazil)
• Sponsoring Organization: USDOE; Office of Energy Research (OER); Office of Health and Environmental Research (OHER)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6425522
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 3 Vol. 99; ISSN JCPSA6; ISSN 0021-9606
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ASYMMETRY
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
COUPLING
EMISSION
ENERGY RANGE
EV RANGE
EV RANGE 10-100
IONIZATION
LINE WIDTHS
OXIDES
OXYGEN COMPOUNDS
PHOTOEMISSION
PHOTOIONIZATION
RESONANCE
SECONDARY EMISSION
YIELDS