Photoionization of N₂X ¹Σ_g⁺, v"=0 and 1 near threshold. Preionization of the Worley–Jenkins Rydberg series.

Journal Article · Sun Jan 01 04:00:00 EST 1984 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.446829· OSTI ID:5310532

Dehmer, Patricia M. ^[1]; Miller, P. J. ^[1]; Chupka, W. A. ^[2]

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1. Argonne National Lab. (ANL), Argonne, IL (United States)
2. Yale Univ., New Haven, CT (United States)

The high resolution relative photoionization cross section for N₂ is reported in the wavelength region from the ionization threshold to 650 Â, with particular attention given to the region between the N₂⁺ X ²Σ_g⁺, v'=0 and 1 ionization limits. Cross sections from both the X ¹Σ_g⁺, v''=0 and 1 vibrational levels were determined in this region, and preionized members of the n ρπ_u ¹Π_u Worley–Jenkins Rydberg series converging to N₂⁺ X ²Σ_g⁺, v' = 1 are observed in both spectra. In the spectrum excited from v'' = 1, the Worley–Jenkins series appears prominently as a result of good Franck–Condon overlap between the N₂⁺ X ¹Σ_g, v"=1 and the N₂⁺ X ²Σ_g⁺, v'=1 levels; the intensities of the series members decrease approximately as 1/n³, in accord with simple theoretical predictions. However, in the spectrum excited from v''=0, the Worley–Jenkins series converging to N₂⁺ X ²Σ_g⁺, v'=1 is weak as a result of a poor Franck–Condon overlap with the ground vibrational level; the intensities of the series members show large deviations from the simple theory as a result of channel interactions with Rydberg states converging to N₂ ⁺A ²Π_u. These perturbing Rydberg states have low photoabsorptionoscillator strengths for excitation from v"=1 (in contrast to excitation from v"=0) and hence have only a small effect on the cross section from the excited vibrational level. Just as in the case of photoionization of H₂, the results demonstrate that channel interaction can redistribute the oscillator strength of a perturbing Rydberg state of low principal quantum number over a number of members of an interacting Rydberg series and that the spectral range affected by the perturber can be much greater than the width of the perturbing level.

• Research Organization: Argonne National Laboratory, Argonne, Illinois 60439
• Sponsoring Organization: USDOE; Office of Naval Research (ONR)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5310532
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 3 Vol. 80; ISSN JCPSA6; ISSN 0021-9606
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
CROSS SECTIONS
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FRANCK-CONDON PRINCIPLE
IONIZATION
NITROGEN
NONMETALS
OSCILLATOR STRENGTHS
PHOTOIONIZATION
RYDBERG STATES
VIBRATIONAL STATES